Their struggles against ignorance and obsolescent traditions are colored with oddly human-like descriptions and nomenclature, prefiguring some major plot revelations towards the end of the story.

The mindrot virus originally manifested itself on the Emergents' home world as a devastating plague, but they subsequently mastered it and learned to use it both as a weapon and as a tool for mental domination.

Emergent culture uses mindrot primarily in the form of a variant which technicians can manipulate in order to release neurotoxins to specific parts of the brain.

By manipulating the brain in this way, Emergent managers induce obsession with a single idea or specialty, which they call Focus, essentially turning people into brilliant appliances.

During his plotting he begins to admire the Emergents' Focus technology, seeing it as the missing link in his lifelong goal to create a true interstellar empire and break the cycle of collapse and rebuild that plagues human planetary civilizations.

Pham announces his plans to free all of the Focused in the entire Emergent civilization, and, if he survives that, to go to the Galactic Center to find the source of the OnOff star and the strange technology remnants that have clearly traveled with it.

Time-measurement details provide an interesting concept in the book: the Qeng Ho measure time primarily in terms of seconds, since the notion of days, months, and years has no usefulness between various star-systems.

But if you looked at it still more closely ... the starting instant was actually about fifteen million seconds later, the 0-second of one of Humankind's first computer operating systems.This massive accumulation of data implies that almost any useful program one could want already exists in the Qeng Ho fleet library, hence the need for computer archaeologists to dig up needed programs, work around their peculiarities and bugs, and assemble them into useful constructs.

That novel posits that space around the Milky Way is divided into concentric layers called "Zones," each being constrained by different laws of physics and each allowing for different degrees of biological and technological advancement.

[3] Nick Gevers called Deepness "one of the best constructed and most absorbing space operas of the decade," and commented that its "shrewd triumph" is that neither optimism nor pessimism defeats the other.

[7] John Clute lauded it as "the most extended example of dramatic irony ever published," in that not only do none of the characters ever learn the truth about the universe, neither does anyone who has not read Fire; he did, however, criticize "the odd dozen-page segments given over to hard-SF geekishness about orbits and computers and stuff.

"[8] The SF Site's Greg L. Johnson considered the novel to be "deceptively straight-forward,"[9] and at Strange Horizons, Amy Harlib praised it as "huge, complex and captivating" and "rich and satisfying and deserving of its award," emphasizing that it is the equal of its predecessor work.

[10] Kirkus Reviews described it as a "chilling, spellbinding dramatization of the horrors of slavery and mind control,"[11] while Publishers Weekly noted that it would "fully engage" readers' sense of wonder, and correctly predicted that it would be nominated for the Hugo Award.