A collaborative effort of AMTA and Barcelona Publishers, made possible by the AMTA archives at Colorado State University, this is a collection of theoretical papers presented at the annual conferences of the National Association for Music Therapy (NAMT) during its formative years. The papers were published in the NAMT annual books of proceedings, which served as the main scholarly publication of the association until it was replaced in 1964 by the Journal of Music Therapy.

Authors include leading pioneers in music therapy as well as renown experts in related fields, including Altshuler, Dreikurs, Fultz, Gaston, Hahn, Klink, Kohut, Masserman, Meyer, Ostwald, and Ruppenthal. The papers are historically significant inasmuch as they reflect how the association and its members were thinking about the nature of music therapy at a time when there was considerable uncertainty about how it should be named or defined. Introductions and commentaries on each paper are provided by Kenneth E. Bruscia.