Book excerpt: These articles describe ideas about contextual performance, organizational citizenship behavior (OCB), and similar patterns of behavior that have been developed by scholars working from very different research traditions. It seems that the different research traditions are converging on the same notion--that besides formal job requirements, other patterns of behavior are also critical for organizational effectiveness and survival. These other patterns of behavior have been relatively ignored until recently, but now scholars are trying to define them, determine exactly why and how they are important for organizations, and identify their antecedents. The results of these research efforts-- described by articles in this issue--will help to make it possible to develop new conceptual and practical tools for managing these important behaviors and in that way promote human performance and organizational effectiveness.