Ability Scores
     Prestige Classes

  Chapter 5: Characters
Ability Scores

Perception (Per)
          Perception is a measure of how well an individualís five senses operate, as well as how well they can interpret what sensations are received. A high perception represents better than average vision and hearing, where an extremely low score can represent blindness or deafness. Perception is most important for rangers, who rely on it for tracking, and rogues, who often rely on their sense of hearing, but could be important to any character where being aware of oneís surroundings is necessary.
          You apply your Perception modifier to:
          Listen, Read Lips, Search, and Spot checks, as well as Wilderness Lore checks when used in conjunction with the Tracking feat
          Any check that relies heavily on perception, such as Appraise and Decipher Script. If you have a negative Perception modifier, these checks are further modified by that modifier, in addition the normal modifier for that skill check.