A skill check used to remember a useful bit of information in a particular field of knowledge. Arcana, Dungeoneering, History, Nature, and Religion are the skills most commonly used to make knowledge checks. Refer to these rules whenever a creature is making a knowledge check, regardless of the skill it is using. Action: No action. A creature either knows or doesn’t know the information. DC: See the Knowledge Checks table. The check DC increases based on the topic and how common the knowledge is. A Dungeon Master might decide that certain information is available only to creatures that have training in the appropriate knowledge skill. Success: The creature recalls a relevant piece of lore in the field of knowledge or recognizes a clue related to it. Failure: The creature doesn’t recall any pertinent information. The Dungeon Master might allow a new check if further information comes to light.
Published in Rules Compendium, page(s) 313, 129.