This document provides a historical overview of the development of industrial and organizational (I/O) psychology from pre-psychology times through the early 1900s. It discusses influential early thinkers like Aristotle, Machiavelli, Hobbes, Locke, and Rousseau and how they related to management concepts. It then focuses on the key founders of I/O psychology in the early 20th century like Munsterberg, Scott, Taylor, and Yerkes and their early applications of psychology to work, personnel selection, and motivation during World War I. It also discusses the establishment of important publications and organizations in this early period of the field.