Abraham Maslow (1908-1970) was an American psychologist best known for his conceptualization of a "hierarchy of human needs" and "self-actualization." He (along with Carl Rogers) is considered to be the founder of humanistic or "Third Force" psychology. This book was first published in 1954, and was revised in 1970. Maslow states in the Preface to the 1970 edition, "I have tried in this revision to incorporate the main lessons of the last sixteen years. These lessons have been considerable ... When this book appeared in 1954 it was essentially an effort to build UPON the classical psychologies available rather than to repudiate them or to establish another rival psychology."