Elliot Aronson is among the 100 most influential psychologists of the 20th Century. He is best known for his theorizing and research on cognitive dissonance theory — one of the most provocative and enduring theories in contemporary psychology — and for his design of the "jigsaw classroom, " an applied method of reducing conflict and prejudice in multiethnic schools. Throughout his illustrious career, he has championed the application of social-psychological theory and methods for solving such pressing social problems as prejudice, energy efficiency, conflict and miscommunication in relationships, and the reasons why many people justify their mistakes rather than learn from them. Aronson is the only psychologist in the history of the American Psychological Association to have won all three of its top awards: for research, teaching, and writing. In this Festschrift, friends, colleagues, and former students write with warmth, clarity, and humor about Aronson’s enduring influence on the field of social psychology and on their own professional lives as researchers, writers, and teachers. Topics covered include contemporary research on cognitive dissonance theory; the changing face of experimentation in social psychology; and applied research on energy policy, education, the legal system, intergroup conflict, and prejudice and discrimination.