From the introduction:
A key to understanding this system is to forget everything you already know about the AD&D weapon and non-weapon proficiency system. It completely replaces the existing AD&D system.
Skills are divided into several categories: physical, mental, mental-physical, fighting styles, brawling, weapon, racial and high-level. This system describes how a player selects the skills his character knows at first level, and how a character can acquire new skills as he advances in level.
Revised August 10, 2000