It is the purpose of this study (1) to discover the nature, history, and present day use of music in therapy; (2) to discover the types of patients at Sonoma State Hospital and their general needs in terms of rehabilitation services; (3) to discover the scope of the total rehabilitation program at Sonoma State Hospital and the part which music therapy plays; and (4) to discover the general principles, problems and techniques of music therapy used at Sonoma State Hospital.