The understanding of psychology is one of the most important roads to success for the modem business man. Industrial and commercial work are in thousandfold contact with mental life. Salesmanship and advertising, learning and training for technical labor , choosing the right position and selecting the right employe, greatest efficiency of work and avoidance of fatigue, treatment of customers and of partners, securing the most favorable conditions for work and adapting the work to one's liking, and ever so many other problems stand b efore the business world and cannot be answered bu t by psychology (Miinsterberg, 1918, p. v).The above quotation by Hugo Miinsterberg is typical of the ambition and confidence (some migh t say overconfidence) of at least some of the founders of industrial-organizational (110) psychology. Although the results of more than 100 years of applying psychology to organizations have caused us to be a bit more humble and circumspect in our pronouncements, it is true that the science and practice of I/0 psychology have made a fair am ount of progress in dealing with Miinsterberg's concerns. The field has had an in teresting and eventful history. As I/0 psychology has expanded and matured, we have seen an increased interest in this history. This is most welcome, as it is our belief that knowledge and appreciation of history is essential fo r deep understanding. Tracing the evolution of ideas in substantive areas of 1/0 psychology and examining the litany of insights, incremental progress, and missteps that resulted in the current state of the field can lead to a richer appreciation and understanding for researchers and practition ers alike.Previous historical overviews of I/0 psychology vary in emphasis, orientation, and detail. Examples include Ferguson (1962)(1963)(1964)(1965),1 who built his history around the Carnegie Institute of Technology's (CIT's) Division of Applied Psychology. Baritz (1960), although critical of industrial psychology's close ties with management, provided a great deal of information about early industrial psychology, as did Napoli (1981) in his history of the psychological profession. A chapter by Hilgard (1987) concentrated on the history of I/0 psychology in the United States; Warr (2007) provided an overview of the development of I/0 ou tside of the United States; and McCollom (1968) and Viteles (1932) gave summaries of the early years of the field both inside and outside of America. Katzell and Austin (1992) offered a contextual approach to American 1/0 psychology history, as did Koppes (2003). A recent book edited by Koppes (2007) took a topical approach to I/0 history. Many other excellent histories of 1/0 psychology have focused on specific conten t areas, individuals, or time We thank Bianca Falbo, Shelly Zedeck, and an anonymous reviewer for their helpful comments. All errors are our own. 1 Leonard W. Ferguson completed a series of pamphlets ~overi n g 14 chapters (one volume and part of another) of a planned 12-volume history of industrial psychology centere...