The Book of All Skies

by Greg Egan

Del lives in a world of many by passing through the Hoops embedded in the ground, her people can walk freely between land that lies beneath a new set of constellations for every circuit they make around the edge of a Hoop. When archaeologists find a copy of the famed Book of All Skies , Del takes delivery of the manuscript in her role as conservator at the Museum of Apasa, hoping it will shed light on the fate of the Tolleans, the ancient civilisation that produced it. But when the book is stolen, the theft sets in motion a series of events that will see her travelling farther than she had ever imagined possible, and her understanding of her world and its history irrevocably transformed.

Genres: Science Fiction, Fiction, Hard Science Fiction, Literature, Science Fiction Fantasy

236 pages, Paperback

Published September 7, 2021

About the author

Greg Egan specialises in hard science fiction stories with mathematical and quantum ontology themes, including the nature of consciousness. Other themes include genetics, simulated reality, posthumanism, mind transfer, sexuality, artificial intelligence, and the superiority of rational naturalism over religion.

He is a Hugo Award winner (and has been shortlisted for the Hugos three other times), and has also won the John W Campbell Memorial Award for Best Novel. Some of his earlier short stories feature strong elements of supernatural horror, while due to his more popular science fiction he is known within the genre for his tendency to deal with complex and highly technical material (including inventive new physics and epistemology) in an unapologetically thorough manner.

Egan is a famously reclusive author when it comes to public appearances, he doesn't attend science fiction conventions, doesn't sign books and there are no photos available of him on the web.

Excerpted from Wikipedia.

Reviews

[Guilherme · Rating 3 out of 5]

I think I figured it out now.

There are two writers named Greg Egan. One is a staunch humanist with a fine insight into the nature of the mind, but which unfortunately suffers from heavy depression. This writer wrote Permutation City, Diaspora and Zendegi.

The other Greg Egan really likes writing equations and figuring out how a planet would look if gravity was inside out, describe that in dizzyingly accurate detail, and just throw in a vaguely pro-science plot so that the whole endeavour is technically a "story" and not topological fanfiction. This Greg wrote the Arrows of Time trilogy, Dichronauts and now The Book of All Skies.

Don't get me wrong, I love a good description of a bridge. I'm just wondering what this Greg has done with the other one's body.

[Claudia · Rating 3 out of 5]

Egan may not be the best novelist, but for sure is among the best in creating unique worlds. His ideas have no match as far as I'm concerned. And even if it's a hard task to imagine how his worlds work, it's definitely a delight to try.

I found it similar in construction with Dichronauts - life and inhabitants of a really strange world.

Plot and characters here are not his best, (except Imogen, whose dry humor is the salt and pepper of the book), they are clearly just a mean to show how a multiply connected space works. And this is the main focus of the story.

For me, the article on his site helped, at least the first part: https://www.gregegan.net/ALLSKIES/01/...

Fans of Egan will enjoy it: it's a treat and a challenge for the mind, as usual.

[Oscar · Rating 2 out of 5]

Greg Egan es un escritor de ciencia ficción dura, a veces tanto como el diamante. Matemáticas, topología, cosmología, física, etc., están presentes en su obra. Egan no escribe sobre sentimientos, sino sobre ideas, ideas que te vuelan la cabeza. En ocasiones es bastante denso, y de ahí que se disfrute más, como es mi caso, a pequeños sorbos, es decir, con sus relatos. Gustará más o menos, pero siempre es interesante.

En esta ocasión, y voy a explicarlo sucintamente (aquí dejo un enlace para mayor información científica: https://www.gregegan.net/ALLSKIES/01/...), nos encontramos en un planeta surcado por dos aros que actúan como portales a otras tierras y culturas. Si no cruzas un aro, permaneces en tu tierra, pero cuando cruzas un aro, ya estás en otro lugar, y si vuelves a darle la vuelta, de nuevo pasas a otro lugar diferente. Más o menos. En este escenario se nos presenta a Del, una arqueóloga empeñada en saber el origen de los Tolleanos, una cultura ancestral desaparecida; se supone que viajaron a las llamadas Tierras Abundantes. Pero, ¿cómo? Es entonces cuando se monta una expedición para ir pasando el aro, y pon ende por sucesivas tierras, hasta encontrar una respuesta.

Me ha gustado más la primera parte, donde brilla más el sentido de la maravilla. Después se convierte en una novela más ética que especulativa.

[Kam Yung Soh · Rating 3 out of 5]

An interesting story about a journey of discovery though a world of many skies. Del, the main character, becomes custodian of a book discovered during an archaeological dig: "The Book of All Skies". But it is immediately stolen. We then get an introduction to the world that Del lives in.

'Hoops' are found in Del's world and when you pass through them, you are still on the world, but transported to a region that features a different sky, implying that the Hoops are a way to connect different regions of the universe together. But Del's world is restricted: an impassable mountain blocks the path through the Hoops in one direction and in the other, the world 'ends' and the Hoops lead to an empty sky with no ground.

In the past, some people from Del's land somehow made it through the mountains to a place called the 'Bountiful Lands' and people have been trying to find the path through again. But Del gets involved in an audacious scheme to bypass the mountains in another way: a journey that would eventually succeed but would be filled with dangers.

As we follow Del's journey, we learn more about the world of the Hoops, including how it may have come about. Through a copy of "The Book of All Skies", we would learn about the hubris of Del's people in the past who though they could control the Hoops and how the world that Del knows came about. And we also learn about people who would reject any change to their way of life and would do anything, including killing, to keep the world the way it is.

The author has a website that contains more information on the physics of the Hoops [ https://www.gregegan.net/ALLSKIES/All... ].

[Daniel Bensen · Rating 1 out of 5]

A lazy morality play.
The science fiction conceit is interesting, but the worldbuilding is thin, the characters thinner, and the story is Communist propaganda. I do think Communism is a bad idea, but that's not why The Book of All Skies upset me so much. It was the rage I felt coming off the story, the contempt Egan seems to feel for anyone who disagrees with him. In his other books, he digs into potential problems with his world-building, but here, he dismisses them with blithe sarcasm. In his rush to convince the reader of his property-less utopia, his writing becomes so sloppy that it comes off as insulting. His characters turn into sketches, the problems they solve a to-do list. Plot holes open, and the book ends abruptly with a hollow shout of "we will resist you!" bravado. The Book of All Skies is a shoddy piece of work, and does not reflect well on Egan's beliefs. If he was serious about them, he would have argued them with more honesty.

[Julie · Rating 3 out of 5]

I love Greg Egan, even though the math and physics goes over my head. He's one of the few authors I insta-buy when he publishes a new book. I like his characters and the weird aliens he dreams up, though in this book we just get humans...but humans that can see heat in the dark!

The cover confused me because I thought that was a diagram of the world but it's not. The world the characters are on are iirc really small spheres. I remember one character saying that if they jumped high enough they could enter the atmosphere, or something like that. Though gravity changes from world to world so I don't know what the standard majority gravity is like. Anyway, so picture this: a small sphere, and then two giant hoops embedded in the world on opposite sides such that only half or less of the hoop is above ground. If you go through a hoop you enter another world! And you can keep going around and enter the hoop again and it's yet another world. But you can't keep going round and round forever. It ends at a "nub" at one end and unpassable mountains at the other end. At the nub you can look through the hoop and see just stars, no land at all.

Each world has different star constellations, which is why the Book of All Skies was named that. The main character, Del, is given the titular book but then it is stolen from her. The book is an old rare book that Del has only seen fragments of, and it supposedly tells the story of an ancient people who made it past the mountains to the "bounteous lands". Some people think it's a myth but others believe it is real and explorers climb all over the mountains looking for the secret path that the ancient people might have taken.

Del meets someone who believes they can cross the nub and reach the bounteous lands that way. And thus Del and her new friend and some other people set off on an adventure.

As others have said the book ends abruptly as you try to turn the page (if reading an e-book) only to find out that you are on the last page already! Despite that it's an interesting story and a strange world (or rather worlds) that these characters live in. They live in darkness or near darkness all the time, there's no sun rising on their worlds except a couple of the worlds have suns and the characters have to be careful to cross that world while the sun is down.

[Mark · Rating 4 out of 5]

The many other reviews here have talked about Mr Egan, the topological fan-fiction and humanist outlook of The Book of All Skies. I agree with both the positives and the negatives. What raises the book up for me is that it was a pure pleasure read.

The world isn't going to end (I mean, not more than it has), the protagonist has nothing more at risk than her own life and the meaning she finds therein, and the story pauses beautifully at several points to rejoice in the wonder of its universe. This is everything I could have asked for from classic SF exploration.

[Dániel Darabos · Rating 3 out of 5]

I liked it! The plot flies straight as an arrow with no side-plots that only become relevant 1,000 pages later. I really needed a book like this after some other recent reading!

I 100% agree with Zach's review about the shortcomings. Some basic questions about the Hoops are never explained. For example, each Hoop has two sides. With two Hoops on each world, that's four portals. But the worlds seem to be organized along a string, just one after the other. (Based on the cover and the single points of Sadema and Celema.) So I guess either both sides of a Hoop go to the same world, or both Hoops have one side for each of the next/previous worlds. There are scenes contradicting both possibilities. They definitely travel from Hoop to Hoop, as in Jierra. But they also travel a lot going round and round on the "ring road" around "the hill". They can even walk from world to world, so it sounds like using the same Hoop? (No idea how big the worlds are, but there are cities in them.)

If the ring road just loops around the same Hoop, why do you have to walk the long ring road around it? Why not circle it closer to the edge in two minutes? On the long way to Celema we have this conversation:

"If we stayed at this edge, and just circled it until we hit the nub ... ?" she joked.

"We could try the same measurements," Montano conceded. "And see if the gap was small enough to bridge. But that would be a lot of work, for no reward."

How is that a joke? I was wondering the same thing! And how is that an answer?

Greg Egan's web page with extra explanations doesn't help me on this either. The very first simple example is "if we ignore one of the Hoops and just consider the effects of a single one." It seems to describe pretty much what's in the novel. What does the other Hoop do?

Okay, enough complaining! I liked the characters. They are not very complex, but each of them is an individual and their personalities have interesting chemistry. There are a few evil-for-no-reason characters, but the people we get to know are all really smart and nice. We see a utopistic society in the vein of News from Nowhere. It also raises a lot of questions that are not answered, but I guess we're here to do topology, not sociology. (I wouldn't have minded.)

The plot has a number of awesome parts that I don't want to spoil. Like suddenly being stranded in an alien land. The ending is indeed abrupt. I kept trying to turn the page. There's not even a "The End" leaf at the end. I don't mind that too much. It's nearly impossible to make an ending satisfying.

PS: I actually figured it all out. It's not well explained in the book, but the worlds are not along a string. They are organized in a cobweb with four neighbors to each world. Hence navigation is pretty challenging. There are many nubs, but Celema is unique. It lies in a "straight line" from Sadema, which they correctly assume would lead them in a loop. Question on Stack Exchange

[Rui · Rating 3 out of 5]

Interesting math, no plot, bad economics

I like Greg Egan. His exploration of gravity in a universe with unusual geometry is interesting. However there isn’t much else to this book. It may have worked better as a shorter article. Also, what’s up with his economics? Half of the world lives in a socialist paradise and the visitors keep asking questions like “who makes sure there’s enough food?” and get replies like “someone does”. A version of this dialog happens enough times to make me think it’s a joke. I’m reminded of the old story of the Russian diplomat who visits London and inquires about who makes sure that the right amount of bread is baked each day. On the other hand, this is central to whatever little plot there is, so I’m not sure it is a joke. Half of the fictional world is so scared of the “dangerous” idea of living this way that they shut themselves out and endure much lower living standards. Seems to me that in history it’s been the socialist countries that shut themselves off and think of capitalism as the dangerous idea that their populations need to be protected from.

[jacob.eru · Rating 4 out of 5]

a very human adventure, sorta steampunk, sorta scifi, quite fun.

[Zack · Rating 3 out of 5]

The early chapters don't do a great job of explaining the hoops' basics, making it harder than it needs to be to understand what's going on. Because of the book's own summary I actually started reading the book with the expectation that the hoops were embedded horizontally in the ground instead of rising up and out of the ground as vertical planes. I may have also been biased by a general expectation that it would be another extremely challenging Egan concept along the lines of Dichronauts.

Not at all. The hoops actually function as very straightforward double-sided portals with each face connecting to a different location. But Egan, as one might expect from him, explains this in ways that only a topologist could love, in one scene actually having two characters talk to each other about tracing paths on a sphere with an example straight out of knot theory.

It's also made harder because no sense of the size scale of the rings is ever really given. I'm not sure why this was omitted, it might be to try to hide information for later reveals but that seems like a dubious benefit given how much harder it makes it for the reader to visualize the world.

Even so, after a reasonably short fraction of the book you'll have figured out what exactly is going on with the characters' use of the hoops and the rest of the book is a very enjoyable math-science-adventure-mystery. I couldn't follow the analogies between gravity and electrostatics but visiting Egan's website yields some pictures that give the general idea without needing to follow any of the math. I wish he'd gone ahead and stuck the images into the text as he did in the Rotational saga.

Although I liked the book overall it lacks any sort of denouement or epilogue to tie off the main character's personal story. The book just ends rather abruptly at nearly the first opportunity after the climactic action and in spite of that action being directly connected to a deeper backstory to reveal. While people like to say that it's about the journey and not the destination it's still nice when somebody leaves a light on for you to welcome you home.

[Andreas · Rating 3 out of 5]

This is a book about a world which is rather weird because of strange objects that give it a very unusual configuration of topology and gravity. The main challenge for the reader is to find out how it works and to try to understand it. As such, the book works just fine (and it helps that the author's website gives a lot of theoretical background although the math involved is clearly beyond me). I found it easy to forgive that the characaters are a little one-dimensional because the journey they take is interesting enough, but the end of the book is very abrupt und unsatisfying, even if there should be a second book to answer the remaining questions.

[Dan Ballard · Rating 4 out of 5]

Open almost like a simple classical fantasy or history set fiction story but slowly Greg Egan's bizaare and physics wild idea world building appears distinguishing it. Fun simple story. Good fun interesting elements

[Tereza Snyder · Rating 2 out of 5]

I'm looking forward to reading a more explicit description of the topology, as my imagination simply wasn't up to decoding the descriptions of this world. I usually get the hang of things in an Egan novel by its end, but this time I just had to shrug and follow the plot for the sake of the characters, of which only the central two have any dimension at all.

Moreso than other recent works, The Book of All Skies reads like a sketch or summary of a deeper, richer work.

[Chris Fox · Rating 3 out of 5]

Anyone else this would be more than three stars, the speculative science is well thought-out but the society is more of that boring 18th century stuff.

I keep flashing back to how good Egan's earlier books were; Quarantine, Distress, Permutation City, Diaspora. His recent stuff is simply not in the same league. The speculative science is not engaging and the moral repartee of his earlier books is gone without trace. Starting around Luminous and Teranesia his writing took a nose dive, then he wove Iranian culture and language into several utterly unengaging books like Zendegi. And while Skies is better than the unreadable Clockwork Rocket trilogy, that's what we call "faint praise."

I want the old Greg Egan back. He did one novella about communication between two quantum worlds that had diverged that was just sensationally good but that was a one-off,

[Username · Rating 5 out of 5]

Welcome to a new age in reviews! With the help of GPT-chat I offer:

The Book of all skies,
A tome of great modest size,
Filled with secrets and lies,
And truth that few realize.

Some hail it as a work of art,
A scientific treatise, with a mind-blowing start,
But others see it as pure fantasy,
A wild flight of the author's fancy.

For in the pages of this book,
Are skies of every hue and nook,
From deep space to distant lands,
And many wonders that no one understands.

Some find its pages dry and dull,
With facts and figures that make them lull,
But others are enthralled and captivated,
By the mysteries that it has created.

So whether you love or hate,
The Book of all skies, it's hard to debate,
That it's a unique and powerful work,
That will leave its mark on those who dare to look.

[Vladimir Ivanov · Rating 4 out of 5]

Пока читал, несколько раз сильно поменял мнение о романе — от первоначального восторга до скуки и скептицизма, и обратно к восторгу, пусть уже более умеренному.


Книга начинается как портальная фентези с крайне самобытным миром — вернее, тысячами крохотных миров, соединенных через порталы в бесконечную цепь. Все эти миры, по грубой прикидке, размером с нашу Цереру или даже меньше; они полностью лишены солнца и понемногу заселены людьми, адаптировавшимися к жизни под звездным светом. Уровень развития у этой странной цивилизации плюс-минус раннесредневековый, так что в основном население размеренно занимается сельским хозяйством; отдельные умы двигают математику или ищут артефакты (в археологическом, не в фентезийном смысле), оставшиеся от древнего толлеанского народа, который, по легенде, в поисках Благословенных Земель ушел по цепочке порталов куда-то так далеко, что все их следы давно сгинули.


Многие хотели бы отправиться на поиски толлеанцев, но есть проблема: ойкумена с одной стороны ограничена непроходимыми горами, полностью перекрывающими портал, а с другой — пустотой. В прямом смысле, очередной портал расположен высоко над землей и пройти в него означает гарантированную смерть от падения с большой высоты. Короче, пересечь природные барьеры невозможно.


Но в любом обществе всегда найдется упертый чудак, который не знает слова «невозможно». И герои романа начинают строить МОСТ, натуральный деревянный мост через бездну. И тут начинается мой любимый жанр про одержимых первопроходцев, которые пересекают все более экзотические миры, где полностью исчезает земная твердь, остается только звездная бездна во всех направлениях, а гравитация закручивается спиралью (этому феномену Иган на своем вебсайте дает строго научное объяснение на десять страниц формул, но можно просто принять, что вот у нас тут такое странное физическое явление, и читать дальше). В своем путешествии герои сталкиваются и с бандитами, и с природными опасностями, постоянно рискуют жизнью и преодолевают; короче, скучать не приходится.


В общем, до середины романа — чистый восторг. Рука тянется поставить девятку авансом.


А потом герои сталкиваются с чужой (но тоже человеческой) культурой, не знающей денег, собственности и классового разделения — и тут все становится резко плохо. Какие-либо события вообще перестают происходить, и вторую половину книги Иган просто рассказывает про анархокоммунизм, о котором, судя по всему, имеет крайне приблизительное представление, потому что в его описании коммунистическое общество устроено примерно так:

- каждый гражданин занимается тем, что ему нравится.

- если гражданину что-то нужно (еда, одежда, инструменты), он просто идет и производит требуемое, ну или просит кого-нибудь подарить ему.

- еды (одежды, инструментов) всегда хватает на всех, потому что... просто хватает, и все.

- никаких властей нет, каждый гражданин и так знает, что нужно обществу, и занимается этим

- органов правопорядка нет, за ненадобностью, ведь преступности тоже нет, потому что... просто нет и все.


Т.е. насколько я понял мысль автора, в таком идеальном обществе на каждого человека, которому нужен, например, топор, всегда найдется другой человек, который обожает делать топоры и дарить их нуждающимся. Откуда у протокоммунистов берутся более сложные штуки, требующие сложного планирования и совместной работы сотен человек — электричество, автомобили, лекарства — Иган не задумывается. В общем, уровень наивности и дурости совершенно запредельный. С такими «друзьями коммунизма» никаких врагов не надо (это я при всей своей симпатии к подобным социальным идеям говорю). Оценка падает, падает, падает куда-то в область 5-6.


Но в последних главах автор вдруг спохватывается и выдает отличнейший эпилог с раскрытием тайн возникновения этого причудливого мира, путешествием на дирижаблях через звездную бездну, и даже с финальным сражением, так что оценка поднимается обратно до восьмерки, где и остается.


Закончил читать с чувством сожаления. Ведь из «Книги всех небес» мог бы получиться совершенно топовый шедевр, если бы удалить из нее этот неуместный социальный памфлет, или хотя бы отдать его другому, более способному в этом плане автору. Ах, какой коллаб мог бы получиться у Игана, например, с Филипом Фармером... или с Желязны... Мечты, мечты. Ну штош, шедевр не случился, но вышла неплохая приключенческая книжка про путешественников в странных пространствах, а это уже кое-что.

[Dan Trefethen · Rating 3 out of 5]

Greg Egan has been using exotic geometries to create new worlds occupied by characters who are human, but somewhat different due to the unique physics of their worlds. Egan is the hardest of hard science fiction writers, in that he provides his research on his website, including the mathematical formulas that underpin his worlds.

In this book, the 'world' is divided into different ones by huge 'hoops' that bisect them, so that people can walk between worlds easily. The math is beyond me, so I just imagined it as a variation of the usual multiverse theme. In a sense, it's a hard SF version of a portal fantasy.

The action is driven when the protagonist, Del, acquires for her museum a rare copy of 'The Book of All Skies' which purports to contain the origin story of how these fractured worlds came to be. But it's stolen, and after a frustrating chase Del signs on to an effort to build a bridge across a gap to find answers in another world that is not quite adjacent to hers (at least not so that you can walk to it). A calamity strands her and one other on the opposite world where they encounter wonders that are more similar to our world. Then, they have to convince the people on the other side to journey back to Del's world.

As is usual with Egan's fiction, there's a lot of infodump about how the physics works. Your tolerance for working through his explanations and trying to visualize it will determine your enjoyment of those parts. For me, I trust that he worked out the math (I can see it on his website, I just can't understand it), and I just skimmed the explanations and called it hand-waving. A very hard, rigorously-worked-out hand-waving.

The ending makes this feel like Egan intends another book; who is that mystery assailant, does he represent a larger organization, and does he tie into the thief earlier in the book?

[Timothy Collins · Rating 4 out of 5]

This book is... different. First and foremost, this is not egans best novel. I'll rank it in the lower half of his work. That said a lesser novel by egan is still a step up from most other writers so it's not a bad novel.

The main problems that I see here is that the very setting is hard to picture. It's a book that I'd suggest you seek out the authors explained page before reading - and even then be prepared to be confused.

The bigger problem is a recurring one in the authors work... the ending. The book doesn't end as much as it just stops. It literally ends in the middle of a conversation. I double checked assuming I'd missed a chapter but no - halfway through a conversation the boom ends.

But then, of course the story isn't the real aim here. The aim of the boom is to play in a earth spread over several different places(?) By "hoops" that seem to act as spatial and perhaps temporal portals. And that's actually interesting.

Expect to be challenged by this novel. But it's worth reading

[Chris Aldridge · Rating 5 out of 5]

A mysterious world with an outlandish geometry

When a curator looses a valuable historical artefact she sets off on an epic journey circumnavigating around an extraordinarily structured artificial world to retrieve it. Her adventures lead her to attempt to locate the land of wonder hinted at by the ancient book. The mysteries of how the world was created and why the path to the lost paradise was suppressed for so long are eventually revealed in this mind bending classic SF book.

I just discovered an additional related gem of a short story available for free on his website called Didicosm. It might be a good idea to read it before this as it’s slightly easier to get your head around, if like me you pretend to yourself that if you really tried you might understand what he’s talking about. Of course if you’re really serious about understanding the science then you could scare the hell out of yourself and read his website explanatory notes. My IQ is definitely the wrong side of 147 so I just skim and look at the pictures. Fortunately I just love to be stretched by his insane imagination, having been overloaded with boring zombies and superhero and war based SF.

[David Walton · Rating 5 out of 5]

There is much of the science described by Greg Egan that I simply don't understand. Nevertheless, I find myself creating images and impressions upon which I can hang the story as it unfolds. Although the worlds inhabited by the characters are alien and strange, the characters invariably display human traits and characteristics with which I can all too readily identify.

So, I try to understand the science, but, for me, it doesn't matter if I don't quite get it. I still finish the book feeling that I've read a good story set against a mysterious and sometimes impenetrable backdrop.

The only criticism I have is that unless this is going to be the first book in a series, the ending is oddly abrupt.

[Evan Þ. · Rating 2 out of 5]

Egan has an interesting scientific concept here, about gravity through large-scale portals. He begins to also have an interesting picture of society in a culture spread through them. But, we don't get much of either of those. We get more of a travelogue through the multiple worlds connected through the portals, with a mystery in the background with a disappointing solution that falls flat.

What's more, the twist in the last half turns out to just be Communism. Which apparently works so beautifully that Egan can't think up any plot points around it aside from "our protagonists find it unusual" and "some people hate it for no discernable reason." It's fine to write Communism, but please do it in an interesting way!

[Will · Rating 4 out of 5]

It's another of those otherwise anodyne stories, except set in a mathematical thought experiment, like Dinochronauts - but it's better, and The clockwork rocket trilogy -but it's shorter.

After Dinochronauts, TBH, I don't trust the science will be revealed in the book itself, and I always look for an appendix, and failing that, as in this case, a page on Egan's website. There is one, I found it helpful, but technically you may want to judge the book on its own merits, rather than including supplemental materials. Having some of the graphs of the way the gravity curves in the book itself, as after all they will have existed in the story. Especially in a self published, e-book, when the companion page has the graphs.

[Martin S. Glover · Rating 5 out of 5]

Not only for geeks!

Gradually picks up pace from an engaging but slow-paced start. It eventually becomes monumental and immense. Greg Egan triumphs in the realm of original and significant ideas.

[Adam Meek · Rating 3 out of 5]

Don't let the math fool you, this isn't really SF: it's a Fairy Tale like Edwin Abbott's Flatland.

If you're interested in exploring freaky megastructures based on advanced physics definitely give this one a go!

[Kenneth Gilmer · Rating 5 out of 5]

It's a slow start but entirely worth it

The story here is simple, as are the characters. The world building is inventive, surprising, and at times dizzying. The scope and ideas are incredible.

[Paul Bard · Rating 3 out of 5]

For real I wasn't sure what any of this was about.

Were they humans? Whats with the heat sensing?

Were we in a ringworld or in a universe with portals like Dan Simmons Hyperion.

I just felt it didn't explain much.

[Plantcore]

Relatively low stakes with very interesting world building. It feels a little bit like setup for a potential next novel?

[Lynn · Rating 4 out of 5]

This was extremely hard to visualize, although I think the cover design helped? I mean, some books would benefit from diagrams? But I loved the idea of the worlds thru the hoop portal, and the political differences encountered. Fascinating archaeology of alien world(s).

[Matt Price · Rating 4 out of 5]

Very nice little book, fun and interesting. Called the 'twist' though...