This chapter of "Principles of School Business Management" identifies management theories that provide a fundamental conceptual knowledge base that school business officials can use to understand the school organizational setting and its influences on the day-to-day operation of the educational process. Particular attention is paid to aspects of organizational theory and behavior that relate to the structure, climate, leadership, and development of organizations. The chapter opens by introducing each of these areas of focus, then presents an overview of the history of management theory from the traditional period prior to 1900 through the eras of scientific management, human relations, behavioral science, and systems, up to the contemporary period that began in 1975. The chapter next discusses organizational structure in depth, discussing major organizational components and the concepts of coupling. Methods for characterizing organizational climate are reviewed next, including open and closed climates, authoritative and participative organization, and the need-press model. The assessment of leadership style and its relationship to effectiveness are the chapter's next topics. The chapter concludes with an examination of the characteristics, prerequisites, and strategies for organizational development. One hundred and three footnotes are provided. (PGD)