This article is an attempt to tell the story of action research as it has developed over the last half century. Action research has become an important part of a number of research programs, especially in the field of education. Action research is a powerful idea centering on humans' ability to break free from deleterious social habits through autonomous, democratic participation. Action research was originally conceived as an adult education program influenced by the work of Eduard Lindeman, Kurt Lewin, John Dewey, and Jean Piaget. A second branch of action research, participatory action research, emerged about 5 years later guided by the sociological work of William Foote Whyte. Participatory action research focused less on democratic processes and egalitarian decision making and more on understanding organizational problems through the eyes of the participants. Chris Argyris and Eric Trist both extended action research in new directions by merging new ideas. (Contains 8 notes.)