From the back of the book:
"The Illithiad is a visually stunning tome that details important information in mind flayers, their mental powers, and their dire plans to control the multiverse.
This "complete book of illithids" covers:
- The anatomy and physiology of the mind flayer.
- The terrible truth about the mind flayer life cycle.
- Illithid-kin, undead mind flayers, and new 'flayer-kin monsters.
- A balanced look at illithid psionic powers.
- Illithid origins, history, theology, psychology, and society.
- A detailed description of a typical mind flayer community.
- Unique mind flayer psionic abilities and items.