The Cosmos Keys

by Glenn Cooper

Buried secrets. Ancient technology. A race against time.

Deep beneath the ruins of Turkey’s underground city of Derinkuyu, archaeologist David Birch makes a discovery that defies history—a bronze device covered in Greek inscriptions, its mechanisms impossibly advanced for its time. The artifact shouldn’t exist. And yet, its intricate design suggests a terrifying someone in the distant past understood the future.

Desperate for answers, David seeks out Eleni Lillakis, a brilliant historian of ancient technology. As they decipher the artifact’s origins, they stumble upon an astonishing legend—the Michaní Peproménou, the Destiny Machine. A device so powerful it was hidden from the world, tied to the secrets of the gods, and capable of glimpsing what’s to come.

But they are not the only ones searching. A secretive cabal, willing to kill to keep the machine’s secrets buried, is closing in. From the shadowed ruins of Athens to the tunnels beneath Nottingham, from hidden crypts to modern-day power struggles, David and Eleni must unlock the truth before the machine falls into the wrong hands. Because if the legends are true, the artifact does more than reveal the future. It can change it.

A Must-Read for Fans of Archaeological Mysteries and Ancient SecretsThe Cosmos Keys is an electrifying archaeological thriller that blends real historical mysteries with pulse-pounding suspense. Fans of The Da Vinci Code, Indiana Jones, and Steve Berry will be swept away by this globe-spanning adventure, where mythology, science, and danger collide in a battle for humanity’s fate.

Genres: Thriller, Fiction

328 pages, Kindle Edition

Published March 20, 2025

About the author

Glenn Cooper is an internationally bestselling thriller writer.

Glenn was born in New York City and grew up in nearby White Plains. He attended White Plains High School before enrolling at Harvard University in Cambridge, Massachusetts where he graduated from Harvard with an honors degree in archaeology. He then attended Tufts University School of Medicine and did his post-doctoral training at the New England Deaconess and the Massachusetts General Hospitals becoming a board-certified specialist in Internal Medicine and Infectious Diseases. After practicing medicine, Glenn began a research career in the pharmaceutical industry which culminated in an eighteen-year position as the Chairman and CEO of a biotechnology company in Massachusetts. Glenn began writing screenplays over twenty years ago and his interest in movies prompted him to attend the graduate program in film production at Boston University. He is currently the chairman of a media company, Lascaux Media, which has produced three independent feature-length films. In 2006 Glenn turned his hand to novel-writing. His debut novel, THE LIBRARY OF THE DEAD, the first in a trilogy, became an international bestseller and was translated into thirty languages. All of his seven published books have become top-ten international best-sellers.

Glenn currently lives in New Hampshire.

Reviews

[Stephen · Rating 3 out of 5]

thanks to the publishers and netgalley for a free copy in return for an open and honest review

This was an easy going read overall with a mixture of thriller and mythology with ancient Greece with a mythic machine which can predict future events. sometimes felt the book missed a little something in the middle as took while to ready getting going.

[Deacon Tom (Feeling Better) · Rating 4 out of 5]

An adventurous story from start to finish!

I really liked this book. It was an interesting adventure between David and Eleni - very similar vibes as the DaVinci code. And what a crazy concept that there's a way to know what future catastrophic events are going to happen. I'll definitely be exploring other books by this author

[Toni Osborne · Rating 4 out of 5]

What an interesting and entertaining concept this high-stake thriller gives us. A story with cutting-edge science and an unforgettable adventure into the heart of ancient mystery. The main character in archaeologist David Birch who can be described as mix between Dr. Henry Jones Jr. in” Indiana Jones and Robert Langdon in” The Da Vinci Code”.

In “The Cosmos Keys” we are in the depths of Turkey’s ancient underground city of Derinkuyu where David Birch unearths an intricate bronze object. He turns to renowned expert on ancient technology, Eleni Lillakis, for help. Their search brings them across Europe but they are not the only one seeking this mysterious artefact…danger awaits at every turn. No force will keep David and Eleni to unravel the secrets behind the Destiny Machine before it is too late for humanity.

The author’s background in archaeology shines, no way to deny that his experiences and studies are behind this story. I find it to be a bit overwhelming at times, my lack of knowledge in Greek historical and religious beliefs definitely did not help. Although the author played well around the subjects by giving us an adventure filled with some excitement.

As for the pacing it keeps a steady tempo even when extensive explanations on history, mythology are at the forefront. In hindsight, not my favourite parts I have to admit that I skimmed pretty fast over some.

I like the characters they are well define and their action visual. I could really imagine their every move. Reading this book I though I was watching a movie on the big screen, popcorn and a soda beside me....dream on.

What a crazy concept ….a contraption that can foresee catastrophes…doesn’t this pique your interest…..

I received this ARC from the Book Whisperer for my thoughts: this is the way I see it.

[Letter From Afifah (Afifah) · Rating 3 out of 5]

✅The Cosmos Keys by Glenn Cooper

Rating:3-3.75 /5 ⭐

#BookReview:
✨Thank you to Book Whisperer & NetGalley for this #ARC. This review was voluntarily written by me.
✨#TheCosmosKeys is a mix for me. It is a tough read but has some messages to ponder.
✨The main theme that I got is colonization, aka artifact stealing. I mean, this is an issue that most, if not all, colonized & formerly colonized countries still face today. This was directly shown in various parts of this story.
✨The thing that I liked about this story is how thoroughly the author explained certain artifacts or events or knowledge, especially related to archaeology. This is understandable when I checked the author’s background. I also really like the flashback parts of this story.
✨Yet, it is difficult for me to keep on reading this story even until the end. I’m not sure why it happened that way because I like the details inserted in this book.
✨My guess is I don’t really vibe with both main characters. They were okay and really good in their adventures, but I don’t truly warm up to them. I also felt that the romance part was rushed, but I know that love can happen at first sight.
✨I know that this book should have a lot of action, suspense and also be thrilling in some parts. However, I don’t get those feelings most of the time, especially in parts that should be suspenseful or thrilling from the writing. But, this may be just me.
✨Lastly, I do suggest this book for anyone looking forward to stories that have a kind of The Da Vinci Code vibe. I know that I’m not really feeling this story, but other readers may love it.

[Richard Derus · Rating 3 out of 5]

Real Rating: 3.5* of five

The Publisher Says: Buried secrets. Ancient technology. A race against time.

Deep beneath the ruins of Turkey’s underground city of Derinkuyu, archaeologist David Birch makes a discovery that defies history—a bronze device covered in Greek inscriptions, its mechanisms impossibly advanced for its time. The artifact shouldn’t exist. And yet, its intricate design suggests a terrifying someone in the distant past understood the future.

Desperate for answers, David seeks out Eleni Lillakis, a brilliant historian of ancient technology. As they decipher the artifact’s origins, they stumble upon an astonishing legend—the Michaní Peproménou, the Destiny Machine. A device so powerful it was hidden from the world, tied to the secrets of the gods, and capable of glimpsing what’s to come.

But they are not the only ones searching. A secretive cabal, willing to kill to keep the machine’s secrets buried, is closing in. From the shadowed ruins of Athens to the tunnels beneath Nottingham, from hidden crypts to modern-day power struggles, David and Eleni must unlock the truth before the machine falls into the wrong hands. Because if the legends are true, the artifact does more than reveal the future. It can change it.

A Must-Read for Fans of Archaeological Mysteries and Ancient Secrets, The Cosmos Keys is an electrifying archaeological thriller that blends real historical mysteries with pulse-pounding suspense. Fans of The Da Vinci Code, Indiana Jones, and Steve Berry will be swept away by this globe-spanning adventure, where mythology, science, and danger collide in a battle for humanity’s fate.

I RECEIVED A DRC FROM THE PUBLISHER VIA NETGALLEY. THANK YOU.

My Review: I really see the comps as good guidance in this case...I ;ike Steve Berry and James Rollins as storytellers, so I'm down with this book as well. It delivers on the promises made above, and does so at a spanking pace.

I'm not ready to go to four stars because, even in the genre, this book's sexism is confrontational. I'm no fan of that. Most of y'all don't seem to care too much but for those who do, be warned.

Lascaux Media asks $5.99 for a Kindlebook. Reasonable value for money.

[Daphne Sharpe · Rating 4 out of 5]

The Library of the Dead was the first book I read from this Author, a panicked birthday present from my son, it turned out to be a lucky buy and a good read, and several more followed over the years.
The Cosmos Key vividly portrays the heat of Athens and those cold underground caves in Turkey and Nottingham.
I did find the characters were introduced too quickly, the locations changed really rapidly and it was hard to keep pace sometimes.
I felt the author really prefers to be writing about the Ancient past, his description of Archimedes and his many experiments, the Myths and Legends of Ancient Greece, were so addictive and really sparked my imagination, the excitement of discovering a device that shouldn’t have been possible to create all those centuries ago, I was fascinated by the Antikythera Mechanism,and got distracted by doing some extra reading alongside this novel, there are so many questions and theories to play with!! I much preferred reading about the Ancient Greek world, their religious beliefs and culture, the Oracle of Delphi, these were so well researched and really brought the book to life.
The modern era exploits seemed rushed and quite contrived, the romance, at first full of promise fizzled out, all the events seemed strained.
The Greek and Roman imaginings were by far the stronger in tone and better written.
The modern era was almost saying, “” I have a marvellous idea for a story, how can modern days and ways accommodate this””?
I gave a four star rating for these reasons.
My thanks to Netgalley and the publishers, Book Whisperer, for my advance copy, freely given in exchange for my honest review. I will leave reviews to Goodreads and Amazon UK upon publication.

[Anne · Rating 5 out of 5]

The Cosmos Keys by Glenn Cooper is a fantastical scavenger hunt for four part to a machine that can foretell future catastrophes. It was build by Greek scholar, Archimedes, in 212 BCE. With the Romans attacking, he broke it into four components and sent it on its way with four young men. This story follows not only their journeys but the journey of American archeologist, David Birch, and Greek astronomer, Dr Eleni Lillakis. It takes a complicated journey during which people die, Birch loses his grant and his job, and they determine what the Mechani Pepromenou has to tell them. It all started when Birch made a fantastic discovery as he and his team were seeking to excavate the Anatolian underground city of Derinkuyu, built millenia before. They had reached seventeen underground floors. He knew he had made a momentous discovery and his curiosity knew no bounds so he packed up the machine and headed to the person who could help. He discovered a group called the Fate Keepers among a group of Hellenistic worshipers of Zeus. I got complicated quickly. The Fate Keeper had been searching for years, and had hidden clues, which took them to England and to Germany.

There were many characters in the story but only a couple of main ones. Cooper managed to keep them sorted and individualized when it could have gotten too complicated. The plot was good, if fantastical and the book was very readable. Excellent characters, good plot, perfect pacing, and a definite goal. I loved every minute of it. It put me in mind of Steve Berry or Dan Brown in style, although totally fantasy. Good read.

I was invited to read The Cosmos Keys by Book Whisperer. All thoughts and opinions are mine. #Netgalley #BookWhisperer #GlennCooper #TheCosmosKeys

[Firetruckmama · Rating 3 out of 5]

I received an eARC of this book from NetGalley and the publisher, for which I thank them.

“The Cosmos Key” is an adventure thriller by Glenn Cooper. This book seemed like a mash-up of Indiana Jones and The da Vinci Code - at least to me. This book follows an archeologist who uncovers something while on a dig in Turkey. He goes to Greece to consult with someone and with her help discovers there’s a lot more to this find than he originally thought. They travel around Europe trying to uncover clues and find more pieces of the discovery. While I liked some of the “past” chapters, because I had heard about the find before (though I thought it was something else then realized I’d mixed up both ancient finds) this wasn’t as enjoyable as I’d hoped. There are some action scenes - evading bad guys, doing some detective work - but I found a summary of what had happened in the story around the 70% mark a bit out of place (it was a lot of rehashing). I think the overall idea of the book was a good one, but for some reason it missed the mark for me (maybe it was the explanations, which were necessary, but I knew some of the myths and history). However, this book was a fast read, so that was a plus. The pacing was a bit uneven too.

[Robert · Rating 4 out of 5]

3.8 Stars rounded up. The Cosmos Key by Glenn Cooper is an archeological pursuit story in which a Harvard professor, David Birch, and his researchers discover an ancient relic while on an archeological dig in Turkey. That relic, which he refers to as the “Destiny Machine,” is part of a larger set of sections that when assembled / connected can supposedly forecast (and perhaps change) future events. Along with Eleni Lillakis, a Greek expert on the Antikythera Mechanism (a similar ancient relic), they attempt to locate and connect all the parts – all while being tracked by a mysterious group as they traveled around Europe.

This story has many similar characteristics to other archeological adventure stories that have a special ancient item being pursued by a variety of interested takers in many locations. Along the way there are interesting historical bits of information such as the background on Archimedes and the city of Derinkuyu, Turkey.

For me, the archeological actions taken by David could be described as “book smart” but his personal actions were just plain foolish, and for me detracted from an otherwise good story. His questionable actions added pages, but little quality to the story.

[Mrs. Kenyon · Rating 4 out of 5]

David is an archeologist on a dig in Turkey when he uncovers a bronze device with Greek writing and a map of the world that wasn’t known when it was created. He asks Eleni for help. She is an expert on ancient technology and their inquiry leads them to secrets that have been hidden for centuries. As they continue to unravel the clues, they must travel across Europe and face others who are also looking for answers. Will David and Eleni solve this ancient puzzle? Is the survival of the human race at stake?

The Cosmos Keys is a stand-alone thriller that will pique the interest of fans of The DaVinci Code and Indiana Jones. No prior knowledge is necessary to enjoy this story, but it will be better for those who already love everything Greek mythology. Cooper’s characters and conspiracies are easy to understand and relate to, which makes this story feel as if you are part of the experience. The Cosmos Keys is a wonderful thriller with a touch of nerdy romance.

[David · Rating 5 out of 5]

When I first read the synopsis for thus book I was kind of cool to the notion but once I started reading, I could not put it down. It has elements of ancient history, science, mythology, A touch of romance and even an apocalyptic ending for good measure. Archaeologist David Birch and Greek mythology expert Eleni Lillakis set out on a quest to recover ancient mechanisms that are said to predict future disasters. Along the way they encounter betrayal and attacks from elements wanting to possess the mechanisms for various reasons. It all adds up to hold onto your seats thriller that traverses both time and geography.
The author uses flashbacks to tell the story of the Michani Pepromenou from their construction through to their rediscovery. I liked this aspect of the book. It lent historical color to the story. I also found most of the characters likeable, flawed though some of them may be.
This is a must read for fans of Dan Brown and Preston and Child. It's a page turner.

[Joan · Rating 5 out of 5]

Review of eBook

In Turkey, David Birch is part of an archaeological dig exploring the underground city of Derinkuyu. As they explore, human bones are discovered. And then, a mysterious bronze object is uncovered. Stunned, David goes to Greece to consult with Eleni Lilakis, an expert on ancient technology.

What is the mysterious artifact?

=========

Told in two timelines . . . the present and the time of the origin of the artifact . . . this story takes readers on an adventure that brings history and mythology into a compelling mystery story. Filled with action and suspense, the unfolding tale keeps readers involved in the story.

Readers who enjoy historical fiction, mystery, and intriguing stories will find much to appreciate here.

Highly recommended.

I received a free copy of this book from The Book Whisperer and am voluntarily leaving an honest review.

[K · Rating 3 out of 5]

A cross between Indiana Jones and Dan Brown stories. A joint dig between American and Turkish archaeologists in Anatolia, Turkey discovers an unusual artefact. David Birch, the American Harvard professor thinks it has a connection to a Greek artefact and travels to Greece to meet with the expert Elani Lillakis, and this is where the book lets itself down in my opinion. David takes the Newly discovered artefact to Greece with him, wrong on so many counts.
In Greece David discovers that Elani is a believer of the Ancient Greek gods and believes his artefact is able to foretell future disasters, but only when it is complete.
Here begins a race across Europe to find the other bits, again like Dan Brown’s stories.
Archeology meets mythology. My thanks to NetGalley and the publishers for the arc. 3.5⭐️

[Luigi · Rating 3 out of 5]

Il libro è carino ma un po' sotto il potenziale dello scrittore, sembra che sia stato scritto frettolosamente e prendendo spunto da testi e anche film precedentemente già usciti.
Tuttavia vorrei spezzare più di una lancia a suo favore: si prova forte empatia verso i protagonisti, ben costruiti e con un bel costrutto storico che ne delinea il carattere e i loro comportamenti. La trama è ben intrallacciata con vari episodi ambientati nel passato, da secoli a decenni prima.
Peccato per il lato antagonista, se così possiamo definirlo, meno pensato e frettoloso, anche se sensato.
Non mi è piaciuto troppo il legame instaurato fra il protagonista e la sua compagna di avventure/scoperta greca.
Il finale mi è piaciuto, qualcosa di inarrestabile che aleggia sin dal principio.
Tre stelle piene (e qualcosina in più).
Consigliato!

[MaggieDay · Rating 3 out of 5]

This book was kindly given to me by the publisher and NetGalley. I found this book to be a mix of highs and lows. The highs included the inclusion of Greek mythology, history, and the Antikythera mechanism, a device I had never heard of before and now find fascinating. I also enjoyed the inclusion of flashback chapters tracing the keys, of the titular cosmos keys, to their modern locations. I also appreciated the realistic outcomes of the protagonist's decisions. One low was the pacing - author's action scenes seemed shoehorned in, as if they were after-thoughts. I didn't find them suspenseful or find they added anything to the story.

[Sarah Elizabeth · Rating 4 out of 5]

Thank you so much to NetGalley and the Publisher for the opportunity to rate and review this title!!

This book hooked me from the first page, and didn’t once let go!! I’m not sure what exactly the official subject is - older but still hunky professor finds gadget that can and does change history and the future - but whether it’s Dan Brown, or now Glenn Cooper, consider it a must buy from me. I truly love standalone thrillers like this, and Cooper is a master at keeping you hooked enough to turn pages late into the night. I look forward to finding more titles from him and going along for the ride!!

[Kristin · Rating 3 out of 5]

2.5 ⭐️ I always enjoy an archaeological dig with some sort of mysterious artifact, and that aspect of this book was really cool. My challenge with this book was that I had a hard time connecting with the characters, and the pacing was strange. Some parts of the book felt very fast while other parts felt very slow. I enjoyed the time jumps with the flashbacks, but sometimes I had a hard time following if we were in the present or in the past.

Overall, an interesting concept, but pacing adjustments could be really helpful to make the story more cohesive.

Thanks NetGalley for the eARC.

[Claudete Takahashi · Rating 5 out of 5]

The Cosmos Keys mixes real facts (there is an Antikythera Mechanism and the underground city of Derinkuyuy really exists) with fiction like the Destiny Machine and it makes a wonderful reading. The story has a lot of mystery and action, it has romance and brings to discussion how mankind might react to learning how things will change and sometimes die. I love history and love to learn about the unkown and the fantastic, if you are a fan of these items this is a book that you must read!
I thank the author, his publisher, and NetGalley for this ARC.

[Tove R. · Rating 4 out of 5]

Mythology, archeology, good old Archimedes and then add more mystery and criminal minds of today, and bang, you have a great story! My favourite part of the story was surprisingly the modern day dig and chase, but all different parts work well together. I liked the keys part in the story, because it gave a bit of a twist, because I have read several books in this genre that reminds me a lot of this one, and to stand out, you need something different and memorable. I recommend this book to readers who enjoy the Indiana Jones kind of a vibe in books.

[Kathryn Breda · Rating 5 out of 5]

It left me somewhere between desperation and eternal hope.

The Cosmos Keys has more thrills, what ifs?, and revelation moments than anything I have read. It was absurd, it was miraculous, life changing and final. I read as many hours a day as my aged eyes can tolerate but this thriller took me by surprise and blew away all my preconceptions of religion, historical fact, and fiction. I was glued to my recliner, reluctant to leave the pages I was on for all but the most basic of needs. Well done!!

[Thomas Norman · Rating 4 out of 5]

no clear ending, the final chapter is empty.

Overall, I found the book to be very well written, engaging and kept my interest up. However, I was very disappointed in the end. The final chapter is blank. I guess you’re just supposed to assume that the end happened but it was quite disappointing. You get to the point where you’re just waiting they’re accepting people. Into the future and then nothing just hanging and waiting. I found that less than fulfilling. The end of the book is just an assumption which really left me hanging and kind of disappointed..

[Jake Murdock · Rating 3 out of 5]

To be honest, the book had a lot of potential. It was so good near the beginning and the writing was making for a really easy read. Sadly, the main reason I gave it three stars is because I feel like the author gave up on the plot about 2/3 of the way through the book and just wanted to finish. I feel like this is a common problem, probably due to deadlines, but it takes a really good book to hide it. This book did not live up to that expectation and it felt rushed and unbelievable at the end. A quick read so I’m not upset but overall could have been a lot better.

[Concha · Rating 4 out of 5]

Thank you to NetGalley and Book Whisperer.
When archaeologist David Birch finds an artefact of Greek origin and unusual manufacture in an excavation in Turkey, he decides to turn to an expert, Eleni Lillakis, to find out more.
An adventure story where we have a narrative in two timelines, the present and the origin of the artifact where the author manages to perfectly combine action and history.
I was hooked from the first chapter. Definitely a very entertaining read.

[Deb · Rating 4 out of 5]

David, a Harvard archaeologist unearths an ancient machine in a dig in Turkey. He goes to Greece to ask for help from Elena Lillakis, a renowned expert on ancient technology. What follows is an adventure to find the other keys to the ancient machine that will tell the future. As they traverse caves, dig up remains, and visit shrines to Zeus, they realize others are also looking for these historic machines and they don't know who to trust.

[Nicki · Rating 5 out of 5]

What a story! Archeologist finds a unique piece of history. The key looks newer than the site he is working on. He takes the item to another country and finds a group called the Fate Keepers. He learns the story behind a group of keys that fit together. Countries are after the pieces How can something this old fit into the future of disasters? The story is interesting and well written. I enjoyed the book.

[John Demos · Rating 3 out of 5]

Overall, I did like the book. I connected with the main characters, the story was interesting and exciting, and the pacing was very good. I realize that this was not the direction that the author wanted to go, but I really wanted there to be a part of the story that explained how the item at the center of the story was actually created. granted, that would have made the book a bit longer, but that’s OK. I think it would’ve fit perfectly right before the denouement/end of the story.

[Rusty Kehl · Rating 5 out of 5]

Excellent. This is the first book that I have read from Mr. Cooper and I loved it. It is well written and he draws all the pieces together in a very subtle way that you don't see coming. Additionally, it was an ending I didn't see coming which is appealing to me. I like the fact that Indiana Jones didn't show up in the sense that there were ancient traps at every turn.The characters are believable and relatable.
I look forward to reading another of Mr. Cooper's books.

[Ellie B · Rating 5 out of 5]

Fabulous adventure tale

Great story, fabulous details, believable and entertaining. I found this story kept me involved to the extent of reading during meals and past my bedtime. The characters are very well developed and human. Much information about the countries and cultures. I would like to travel to these locals. My brain hurts from learning much about technology, and the human spirit. Highly recommend you delve into the depths of this adventure.

[Ashley Elliott Shaw · Rating 4 out of 5]

I really enjoyed this book. It was an interesting adventure between David and Eleni - very similar vibes as the DaVinci code. And what a crazy concept that there's a way to know what future catastrophic events are going to happen. I'll definitely be exploring other books by this author! Thank you so much to NetGalley and the publisher for a chance to read this book.

[Stacy · Rating 4 out of 5]

Thanks to NetGalley and Book Whisperer for an ARC in exchange for an honest review.

3.5 stars

David Birch finds an interesting artifact on a dig in Turkey's ancient underground leads David on a wild dash across Europe to solve a 2000 year old mystery. I am always impressed when authors can take an ancient artifact and turn it into a solvable modern adventure.