Abstract
Lewis Mumford is America's most prolific, popularly read, and lavishly honored theoretician of cities. Many consider him a master of organic and humanistic planning thought. There is little interpretive scholarship on his writings, however, so his complex arguments remain inaccessible to most professionals. To overcome that barrier this article describes and assesses Mumford's planning thought. It also explores reasons Mumford's later writings have not been used extensively in recent American planning practice and education: that he never wrote a reference text for the practicing planner; that he was too critical of the social science emphasis, positivist philosophy, and bureaucratic orientation of planning education; and that he demanded more radical change in physical planning than most established professionals were willing to accept.