Catalyst: A Dark Descent into Delirium

by Ianic Mathieu

Genres: Horror

293 pages, Paperback

Published May 27, 2025

About the author

Ianic Mathieu is a writer with decades of experience crafting stories across a wide range of formats, including short films, interactive video games, novels, songs, and short stories. His work spans an impressive breadth of themes and eras: from psychological dramas set in the 1950s and 1970s (The Fisherman’s Wife and Catalyst), to the sweeping devastation of the plague across Italy, France, and England (Tales of the Black Death saga), to the gritty realities of Sudbury’s nickel-mining era (Salt Bullets). He also delves into techno-thrilling territory with the Breacher Story series, exploring hacking and the near future—set to be published soon.

Reviews

[Natascha · Rating 2 out of 5]

Ich mag solche Mixed-Media-Bücher und lese sie zwischendurch immer mal wieder ganz gerne, aber mit der Zeit nutzen sich diese Gimmicks ab, wenn die Geschichte nicht auch entsprechend überzeugen kann. Leider ist das bei Catalyst der Fall.

Die Handlung fühlt sich insgesamt zu übertrieben an und gleichzeitig hat man am Ende das Gefühl, dass es an Tiefe fehlt die einem die Charaktere hätte näher bringen können. Natürlich will man wissen wie es ausgeht, aber weil sich die Personen nicht wie reale Menschen anfühlen ist einem ihr Schicksal relativ egal.

Nett fand ich die Idee, dass man sein eigenes Ende wählen kann wenn man möchte, auch wenn ich die Auflösung ziemlich absurd fand. Allein das drei Enden für die gleiche Geschichte möglich wären zeigt für mich, dass man hier sehr offen sein muss was die Erklärungen angeht.

[Rainbow Goth · Rating 4 out of 5]

I thoroughly enjoyed this book and I'm genuinely pleased that I decided to read it. One observation I have is that it might be more engaging in print format rather than as an ebook. In print, you could easily flip back and forth between pages, which would enhance the reading experience, especially given the book's interactive elements.

That said, I found the layout of the book to be wonderfully organised, making it a quick yet immersive read that I really could sink my teeth into. The presentation contributed to my overall enjoyment, as it seamlessly guided me through the content.

The endings were quite unexpected, especially since there were multiple options available. However, I did run into a bit of a snag: while I followed along, counting the light, shaded, and dark choices to determine my ending, I ended up with an equal tally of light and dark. Unfortunately, there was no option provided for this scenario. As a result, I ended up reading all the different endings anyway—something I might have done out of curiosity regardless—but it would have been nice to see a tiebreaker option or an alternative suggestion for readers in similar situations.

On a positive note, the illustrations throughout the book were simply brilliant and added a delightful touch to the overall feel of the narrative. They not only complemented the text but also enhanced the immersive experience, making the story visually engaging.

However, I did find the final ending to be somewhat anticlimactic. Given the intense build-up, I had hoped for a more explosive conclusion. Although it left me wanting a bit more, my overall experience was very positive. I believe this book would particularly appeal to readers who enjoy interactive elements like quizzes and games, as it offers a unique way to engage with the storyline.

Thanks to the author, publishers and BookSirens for the ARC of this book. The review is my own.

[Kelsey · Rating 4 out of 5]

We follow Dr. Novak, a psychologist, who is tasked with reviewing a series of recorded therapy sessions.

Told in mixed media - newspaper clippings, audio, letters, post-it notes and Dr. Novak’s own journal.

The reader is given the opportunity to determine one of three outcomes for Dr. Novak at the end. Is he sane or delirious?

I decided to read it without coming to my own conclusions, but I thought that it was an interesting aspect to add to the book.

All in all I really liked this one. I was drawn into the therapy sessions, and it was interesting being in Dr. Novak’s mind.

I received an advance review copy for free from BookSirens, and I am leaving this review voluntarily.

[Sheri Corriero · Rating 5 out of 5]

This is the first time I have read something like this. It is a whole experience, not just a book. We are peaking into Dr. Novak’s journal and session notes and it paints a picture of how he thinks. It is presented like a journal. There are some pictures. I actually felt like I was going through someone’s file. I loved how it lead me down Novak’s path but there were different endings you could choose from, depending on how you experienced the information given. I received an advance review copy for free through BookSirens, and I am leaving this review voluntarily.

[Makayla Jenkins · Rating 5 out of 5]

I was pleasantly surprised with this book! I got to admit I couldn’t put it down. I also read each ending as well. I’ve never read a book quite like this one, so this was a treat. Bravo.

I received an advance review copy for free, and I am leaving this review voluntarily.

[Aura · Rating 5 out of 5]

Arc reader review.

All right, all right.

This is my first time reading such a book, the way it is made is absolutely fascinating and makes the reading experience so different, everything is really immersive, from the diary entries, to the doodles etc.

I am really glad I picked up the book as an arc reader, I do not regret it one bit.

[Yvonne · Rating 4 out of 5]

This is not your typical novel. It’s more like a case file, presented as transcripts of therapy recordings, journal entries and letters, with illustrated post-it notes, and drawings. As a fan of mysteries/thrillers, while unsettling, it was a welcome change to simply words on a page.

While I won’t go into spoilers, and there is so much to unpack, the story revolves around a psychiatrist reviewing transcripts of a disturbing case that gradually blurs the lines between observation and obsession. We are told: “The documents and materials presented before you have been gathered for research purposes, so that those in the field may learn from the tragic events that transpired between November 27, 1972, and January 4, 1973.”

The transcripts, office notes, and mental unraveling are a mix between clinical, intimate and uncomfortable. At times, I was creeped out - not just by what was happening, but by the visuals and changing narrative.

An interesting twist, should you want to participate, is you can influence the outcome by “weighing in on Dr. Novak’s conclusions. This, in turn, may lead to a different conclusion in Dr. Novak’s narrative.”

I received a digital advance copy for a voluntary review and while it still works, it would work better in print. There’s just something about physically flipping through pages, seeing annotations and visuals on paper, that would have made the experience even more immersive.

The themes are heavy - mental illness, death, suicide, and psychological deterioration - and there is a clear content warning.

The ending surprised me and the book left me a little uneasy which is what a good thriller does - even if I don’t really want to be uneasy! Some questions remained unanswered, and the ending wasn’t what I expected, but maybe that was intentional. Still, it’s a unique read that stands out for creativity, atmosphere, and layers.

If you enjoy experimental type fiction, psychological thrillers, or books that make you question what’s real and what’s imagined, Catalyst should pull you in - and stay with you. I’m not sure yet if I am brave enough to try Dr. Novak’s Puzzle Book though.

[Susan Belman · Rating 4 out of 5]

This book isn’t just something you read—it’s something you go through. This was my first time reading something like this, and I was hooked from the start.

We follow Dr. Novak, a psychologist tasked with reviewing a series of recorded therapy sessions, and the story unfolds through a creative mixed-media format—journal entries, audio transcripts, letters, post-it notes, even newspaper clippings. That format, combined with eerie and brilliant illustrations throughout, made the whole thing feel incredibly immersive and visually engaging. Loved this—such a unique idea!

One thing to note: I read an e-copy, but this would be so much more fun as a physical book. The ability to flip back and forth, linger on the visuals, and fully absorb the layered format would definitely enhance the experience.

One of the most interesting elements is that readers are given the chance to decide the outcome for Dr. Novak. Is he grounded in reality… or has he spiraled into madness? The therapy sessions themselves were fascinating, and being inside Dr. Novak’s mind gave the story a layered, psychological edge that I really enjoyed.

If you’re looking for something dark, original, and deeply atmospheric, this one is definitely worth picking up.

[A · Rating 5 out of 5]

Thanks to BookSirens for the avanced reader copy , this deserves the 5 star review. After sampling some of the chapers i was inquisitive due to the different nature of the layout of this book. It has diary inserts, observation sheets and you get an insight into some of the clients as part of Dr Novak being a psychologist. It has alot of mixed media so isnt your traditional read but it also made it very quick to get through.

It was laid out really well with a variety of mixed media to keep the reader interested, you are taken on a journey with Dr Novak with going over previous tapes from a client. This is where it gets interesting as you become part of the clients world and events, its done really well and i found myself sitting for long periods of time. Lots of dark chapters with the client and sad at times where it involves trauma, but it has the deeper meaning of how trauma can affect people through their lifes and their inprint from their parents.

A very dark dark, moody , disturbing in some area and a deep dive into the inner mind of how people can work.

[Amy · Rating 5 out of 5]

This was a very interesting book that requires the reader to come to their own conclusions. It is an interesting look into one psychologist’s descent into madness, while he analyzes audio recordings of a patient of one of his colleagues. It is hard to decipher if his madness is a result of analyzing these audio recordings or if the way he interprets the recordings is a result of his madness. I enjoyed the mix of transcripts, notes, and documents that are used to piece together the story. While it was definitely a much different type of read than I typically search out, it was very well done and very unique.

I received an advance review copy for free, and I am leaving this review voluntarily.

[Claire · Rating 4 out of 5]

I received a free ARC of this book and I am leaving an honest and voluntary review. Dr Novak is assigned to review therapy notes, but finds himself getting caught in a dark world where his own sanity is at stake. This was a really interesting book and the way it was presented (through transcripts, post it notes and letters was a clever way of keeping attention. Not a spoiler as sunch, but do the academic excercise as you go along, trust me! I'm considering purchasing Dr Nokak's puzzle book as a follow on to this as I really enjoyed the story.

[Stephani Gozalo Cavallini · Rating 4 out of 5]

I really really liked the format of this book, I saw it at an indie library in Montreal and I had to have it, glad I did.
To get into the mind of a professional psychotherapist and his job, his opinions and the questions that arise with every other sentence the client said on the tapes.
The back and forth between the “two” was interesting, to see the different aspects and different opinions.
Graphics, notes, drawings.

[Sara · Rating 3 out of 5]

I liked how the book was set up. The old school comic book feel added an experience to the book instead of just dialog. Definitely not scary or horrific but more of OCD Fight Club feel, without the fighting. It was a slow burn to a simmer, but it was intriguing to the end.

I received an advance review copy for free, and I am leaving this review voluntarily.

[Faith Halverson · Rating 5 out of 5]

If you're a fan of House of Leaves, S., We Used to Live Here, or choose your own adventure books, read this IMMEDIATELY. I'm always on the hunt for books like this, mind-bending, twisty, make you feel like you're losing your mind while reading it. The layout and the images in this book were beautiful and I need to immediately go buy the "puzzle book" based on this.

[Evan Main · Rating 4 out of 5]

Following Dr. Novak through his research was a twisted and fun adventure. I really enjoyed the build through the story. Being able to jump back and forth while doing my own investigating made this a submersible story.

[Becky Honey · Rating 1 out of 5]

It thinks it’s doing and saying so much more than it is. It reminds me of a short story I wrote for school when I was 14. I thought I was edgy then too.

DNFed around 25% through.

[Dhuaine · Rating 5 out of 5]

Have you ever thought, what if Journal 29 was a novel? With similar sense of mystery and puzzles to solve, but with way more story involved and not as much puzzling.

Well, Catalyst scratches that itch, somewhat. The story is maybe not as intricate as it might seem at first glance (I may have been overhyped for it), there is little need to backtrack through the book. There are no puzzles that you can solve beforehand. You can theorize, but otherwise it's a linear romp through transcripts, annotations, diary entries, post-it notes, etc. It's a intriguing story and it's a genuine wonder to navigate. I strongly recommend the physical book. The format is what makes it great! It's amazing that indie print on demand makes such gems possible, I can only imagine how impossible it would be to get a book like this traditionally published. I'd love to see more books attempting this variant of storytelling. It's a whole experience.

The story itself is more like 4.5 - it's not that convoluted and you're pretty much only along for the ride. It was also more straightforward than I expected, but that at least makes it approachable and easy to digest. It's also not that dark - the content warnings for suicide etc. are appropriate, but if you're not at risk, you won't have nightmares or anything. It also helps that the main narrator is rather unlikable so I wasn't exactly worried about what might happen to them. All in all, a great adventure, especially if you like experiments with book formatting.