Burrhus Frederic Skinner (March 20, 1904 – August 18, 1990) was an American psychologist, behaviourist, author, inventor, and social philosopher. He was a professor of psychology at Harvard University from 1958 until his retirement in 1974. Skinner was a prolific author, having published 21 books and 180 articles. He imagined the application of his ideas to the design of a human community in his utopian novel, Walden Two (1948), while his analysis of human behaviour culminated in his work, Verbal behaviour.