When do we want people to agree with us and when do we not want people to agree with us? How can we convince someone that their views are wrong? Such questions are raised by SOCIAL INFLUENCE. This milestone text provides both a straightforward introduction to the topic of social influence for the beginning student and a sophisticated theoretical analysis of social influence processes for the more knowledgeable reader. The author summarizes a vast literature, integrating many differing views on social influence in a coherent and meaningful pattern. He reevaluates and reinterprets the findings of many classic studies, into an integrative self-categorization theory, which may resolve many inconsistencies in the literature and account for a diverse set of social influence phenomena.