The Psionics Handbook is a Dungeons and Dragons Third Edition splatbook that adds a psionics system to that version of the game along with two new base classes (the Psion and Psychic Warrior) and four prestige classes (Metamind, Pyrokineticist, Slayer, and Soulknife), which is probably the lowest number of prestige classes found in any Third Edition splatbook. It was the second hardback splatbook released for that version of the game (the first being Monsters of Faerun).
For some insanely idiotic reason, in addition to a psionics system, it also added a completely separate psionic combat system, which nobody really understood or gave a shit about because it required more math than FATAL and the Apollo missions put together. Here's a small excerpt: "The attacker sets the defender's will save DC with a d20 roll modified by two additional components: the attacker's appropriate ability modifier and the DC modifier. The attacker's ability modifier depends on the specific attack mode used. The DC modifier is determined by the defense mode raised by the defender, if any, which is found by cross-referencing the attack mode and defense mode on Table 4-1..." nigga shut the fuck up, nobody's going to keep track of all that shit. After 3.5e was released, one of the first things that WotC did was replace the Psionics Handbook with the Expanded Psionics Handbook, which got rid of psionic combat, much to everyone's relief. Help