This document discusses organizational development (OD) by defining it, outlining its evolution and characteristics, and describing common OD interventions. It defines OD as planned efforts to increase organizational effectiveness through behavioral science interventions. Key figures who advanced OD include Blake and Mouton, Shepard, McGregor, and Beckhard. Common interventions discussed include action research, sensitivity training, surveys, and socio-technical methods. Generations of OD moved from individual to larger scale interventions focused on leadership, transformation, and learning organizations.