Allow me to open this review with one statement: Even for Halo fans, Cryptum may be hard to follow at times.

That being said, author Greg Bear crafts a science fiction novel that even people who aren't fans of the Halo franchise will appreciate for its complexity. Honestly, the complexity of this novel is what makes it enjoyable, if not hard to read at times. For example, Bear introduces new words and concepts without, in most cases, any explanation up front, leading the reader along a particular string of thought before the explanation is if fulfilled. However, while this makes the novel harder to understand in some cases, it also makes it more rewarding to read once you have gleaned a generous amount of lore and fully understand the concept that Bear introduces.

The main characters of this novel are two humans and two Forerunners which, according to the Halo franchise's lore, are highly advanced alien beings (who are very similar to humans otherwise) who both doom and save humanity in one breath. The two Forerunners and their culture are the primary topic of this novel, with the two humans' story being mostly saved for Bear's upcoming Primorium.

Forerunner political upheaval and class warfare on a galactic scale result in the creation of the Halos, gigantic ring worlds (idea courtesy of Larry Niven) that serve as, essentially, the flamethrowers of the universe. These massive weapons are intended to cleanse the galaxies of all sentient life so as to deprive the infectious and parasitic Flood of victims should they return from the farthest reaches of space.

Cryptum is a character-driven novel, with a healthy dash of gorgeous lore storytelling and well-written environments that nearly pop off of the page. A majority of the book sees the two Forerunners, young Born Stellar and the previously cryogenically frozen and infamous military hero turned political dissident, the Didact, realizing their places in the overarching plans of the Librarian, another Forerunner who is dedicated to preserving each and every one of the millions of lifeforms spread across the universe (seemingly just in time for the culmination of the political upheaval).

The personal histories of each of these characters and their connections run far, far deeper than they appear to on the surface, and the reader will not understand the true nature of these relationships unless they finish the novel. Bear weaves a mystical thread of connection throughout the novel that leads to the very last page.

I'd recommend this book for fans of science fiction who are looking for a new twist on the genre that is inspired by one of the most critically acclaimed science fiction video games in history. I'd also recommend this book for fans of the Halo franchise who are interested in getting into the Halo series' books (as it is the first chronological book in the line) and fleshing our their understanding of the lore. An excellent installment by Greg Bear, for sure!