This article summarizes the life and work of America's most influential counselor and psychotherapist, Carl Rogers. He developed the client-centered, person-centered approach; popularized the term client; pioneered the recording of counseling cases; conducted landmark research on counseling and psychotherapy; and was a leader in the humanistic psychology movement, and more. Later, he applied the person-centered approach to resolving intergroup and international conflict. Work on the client-centered approach continues, and current research validates many of Rogers's earlier contributions.