Organizational behavior is the field that studies how individuals, groups, and structures affect behavior within organizations. It aims to apply this knowledge to improve organizational effectiveness. Individual behavior can be understood through three models: the basic model, S-R model, and MARS model. The historical evolution of organizational behavior includes scientific management, bureaucratic, and Hawthorne studies approaches. Organizational behavior integrates factors to provide a simple understanding of human behavior at interpersonal, group, inter-group, and organizational levels.