It is estim ated that m ore than half o f the w orld’s psychologists today live and work in the United States, and m ore than half o f those are employed outside o f the colleges and universities where the science o f psychology began. Most o f these applied psychologists work in clinical and counseling settings, but approximately one third o f them are employed in business and industry. This chapter describes the origins o f psychology in service to the world of business through its po in t o f initial entry, the application o f the new scientific psychology to the world o f advertising, an applied field that began m ore than 100 years ago.