Like Simmons' earlier series, the Hyperion Cantos, it is a form of "literary science fiction"; it relies heavily on intertextuality, in this case with Homer and Shakespeare as well as references to Marcel Proust's À la recherche du temps perdu (or In Search of Lost Time) and Vladimir Nabokov's novel Ada or Ardor: A Family Chronicle.
As in Le Guin's Hainish series, Simmons places the action of Ilium in a vast and complex universe made of relatively plausible technological and scientific elements.
[1] The series centers on three main character groups: that of the scholic Hockenberry, Helen and Greek and Trojan warriors from the Iliad; Daeman, Harman, Ada and the other humans of Earth; and the moravecs, specifically Mahnmut the Europan and Orphu of Io.
This reproductive method causes many children not to know their father, as well as helps to break incest taboos in that the firmary, which controls the fertilization, protects against a child of close relatives being born.
One of the most notable references is when the old woman Savi calls the current people of Earth eloi, using the word as an expression of her disgust of their self-indulgent society, lack of culture and ignorance of their past.
Mahnmut of Europa is identified as a Shakespearean scholar as in the first chapter he is introduced where he analyzes Sonnet 116 in order to send it to his correspondent, Orphu of Io, and it is here that Shakespeare's influence on Ilium begins.
Proustian memory investigations had a heavy hand in the novel's making, which helps explain why Simmons chose Ada or Ardor: A Family Chronicle over something more well-understood of Nabokov's, such as Pale Fire.
Ada or Ardor was written in such a structure as to mimic someone recalling their own memories, a subject which Proust explores in his work À la recherche du temps perdu.