Kurt Lewin is best known as the foremost proponent of field theory - the notion that individuals, and the groups that surround them, are not independent elements but interdependent. The social group, Lewin believed, is the primary shaper of a person's thoughts, feelings and behaviour. The concept is now so commonly held that it's hard to imagine that it was ever considered groundbreaking. Yet it doesn't begin to cover the range of pioneering work that Lewin contributed to social and personality psychology. Through his prolific research and writing, he brought innovative concepts to both the methods and the language of social psychology. Throughout his life, Lewin struggled to adhere to his self-imposed vision of the researcher who maintains a constant intense tension between theory and reality. His favourite metaphor was that of a bridge, connecting research with action, laboratory with community. This reprinted volume seeks to reacquaint students and historians of psychology with Lewin's enduring contributions to social psychology. Translated from the German, it provides a foray into Lewin's work and into his idiosyncratic vision.