This is the second edition of a 1980 publication, in which contributors explored theory and history by focusing on some of the central figures in the development of the discipline. Chapters focus on psychophysics (the oldest incarnation of experimental psychology) and on Gestalt, cognitive and evolutionary psychology. This text is considerably updated and expanded, covering such seminal influences as Fechner, G.E. Muller, Wundt, Galton, James, Darwin, Baldwin and Vygotsky; such topics as the Americanization of psychology and psychoanalysis, the relationship between politics and psychology in the United States and the contrasting development of the concept of the self in Western and Eastern psychology; and reprinting chapters originally contributed by B.F. Skinner and Jean Piaget. This book documents the development of a continually evolving field - one that had a profound influence on the thought and culture of the 20th century.