achilles1515 | 17 points
Halo: Cryptum is a military science fiction novel by Greg Bear, based on the Halo series of video games. The book was released in January 2011 and is the eighth Halo book (the seventh novel) and the first in the trilogy of novels focusing on the Forerunners, called The Forerunner Saga. Cryptum was released in hardcover, e-book, and audiobook following 2009's Halo: Evolutions, a collection of Halo short stories. It is succeeded by Primordium, published in January 2012, and Silentium, in March 2013. Bear was given little restriction on the story of the novel; the Halo universe had not yet been explored in that time period.