Human Motivation, originally published in 1987, offers a broad overview of theory and research from the perspective of a distinguished psychologist whose creative empirical studies of human motives span forty years. David McClelland describes methods for measuring motives, the development of motives out of natural incentives and the relationship of motives to emotions, to values and to performance under a variety of conditions. He examines four major motive systems - achievement, power, affiliation and avoidance - reviewing and evaluating research on how these motive systems affect behaviour....