This document provides an overview of organization development (OD). It discusses that OD is a relatively new field that emerged in the 1950s and 1960s to help organizations function better through planned interventions. The document outlines several models of OD, including Lewin's three-stage change model, Lippitt et al.'s seven stage consulting process, and Burke-Litwin's model of transactional and transformational change. It also discusses key aspects of OD like participation, teams, interventions, diagnosis, and managing the change process.