The literature on motivation theory is growing rapidly due to increased interest by leaders in all types of organizations in social-psychology variables such as internal commitment and motivation to work. This paper presents an overview of motivational research, covering early behavior theories such as scientific management and human relations, and then discusses three major categories of contemporary motivation theory: content theories, process theories, and reinforcement theory. Content theories, like those developed by Maslow, deal with basic concepts of needs that begin, stimulate, or cause behavior. Process theories are concerned with understanding the reasoning behind the choice of a particular behavior pattern to accomplish work goals. The reinforcement theory of motivation is briefly defined in Skinner's terms: individuals are passive, merely mediating between forces, and study of human motivation should focus on measurable and observable behavior rather than needs or goals. An integrative motivational model is presented, and practical applications of current motivational research are examined. The concluding statements note that, although much of the theoretical and empirical material on motivation is contradictory, increased practical application of the knowledge gained by research is needed to find solutions for current organizational dilemmas. (FG)