2007 by Henry L. Roediger III, Yadin Dudai, and Susan M. Fitzpatrick. All rights reserved. This part presents four chapters on the concept of context. The first chapter develops a definition of what is meant by the term "context" that relates to the history of research that has made the term so common today. The second considers three specific problems-mood congruence, mood dependence and mood mediation-that present different sides to the general question of how affective states, such as happiness and sadness, function as internal or experiential contexts for memory and cognition. The third focuses on the relationship between memory and context. The fourth chapter presents a synthesis of the chapters in this part.