An examination of the basic premises and principles of psycho-therapy with emphasis on the relationship, interpersonal processes, and communication patterns that underlie cognitive-behavioral psychotherapy. A survey of the major types of psychotherapy: psychoanalysis, nondirective, behavioral, and experiential and existential; basic principles of these types of therapy and their application to individual adults, adolescents and children, as well as to family, marital and group settings discussed. Current research on effectiveness and utility included.