Pathfinder Chronicle

Source Inner Sea World Guide

Numerous volumes and editions of the Pathfinder Chronicles exist. When used as a reference (an action that typically takes 1d4 full rounds of searching the text), a Pathfinder Chronicle grants a +2 circumstance bonus on a specific Knowledge check. Each Pathfinder Chronicle grants this bonus to a different type of Knowledge, but regardless of which type that particular chronicle is focused on, the overall cost of the book remains the same.