Over the two years that 3rd edition had been out certain power-gaming abuses had become evident. In response to this, the 3.5 rules edition was released to prevent such min/maxing tactics such as front-loading (Picking one level of several classes so as to gain the most abilities each level). Shortly after its release, came the expanded psionics handbook which took much of the bite out of their abilities, referred to as nerfing. Much of the life span of third edition was held by 3.5e.

Races: Dwarf, Elf, Gnome, Half-Elf, Half-Orc, Halfling, Human
Classes: Barbarian, Bard, Cleric, Druid, Fighter, Monk, Paladin, Ranger, Rogue, Sorcerer, Wizard
Alignments: Lawful Good, Lawful Neutral, Lawful Evil, Neutral Good, Neutral, Neutral Evil, Chaotic Good, Chaotic Neutral, Chaotic Evil
Level Range: 1 and up

Players Handbook: This book covers everything needed for character creation including races, classes, skills, feats, equipment, and spells. It also covers all the rules that a player needs to know such as combat procedures.

Players Handbook II: This book adds a few more classes such as the Beguiler, Dragon Shaman, Duskblade, and Knight. It also gives the usual handout of feats and spells like most books of this edition. It digs further into designing your character's background and offers new things your character can have, such as joining affiliations and teamwork benefits. The most handy part of this book is the rules about rebuilding your character.

Dungeon Masters Guide: The DMG covers subraces, making new classes, prestige races, NPCs, special abilities, environmental hazards, ability checks, saving throws, dungeon design, experience awards, treasure, magic items and magic item creation. A new element in this version was the addition of epic level rules, allowing the core rulebooks to progress to any level without need of any other books.

Dungeon Masters Guide II: DMG2 focuses mainlu on the campaign, NPCs and endevors that characters may be interested in, such as running a business. Even more magic items are added like with every book produced in this edition of the game.

Monster Manual: This book retools several monsters from the 3.0 Monster Manual so as to take advantage of the new system better than its original incarnation.

Expanded Psionics Handbook: Not actually an expansion, but a replacement for the Psionics Handbook. Attack modes were turned into powers, eliminating a key feature normally associated with all of the pervious psionics rules. This book presents much of the same material as the Psionics Handbook, but revised and retooled to prevent abuses.

Settings: With the Open Game License in full gear, there are more settings than anyone could possibly count have been introduced.