This study of innovation brings together a wide array of topics under a theoretical model consisting of two basic dimensions: aggregation level (individual, group, organization, and society) and aspects of progress (generation, evaluation, implementation, and diffusion of new ideas and products). The readings, many appearing here for the first time, were written by an international group of experts--including Eric von Hippel, Arthur L. Stinchcombe, L. Richard Hoffman, and Robert A. Burgelman--and represent a variety of disciplines, including psychology, economics, sociology, political science, social anthropology, marketing, engineering, and education.