Fritz Hegi explores the impact of music both as a musician and as a music therapist. In the book "Improvisation and Music Therapy" (1986), a phenomenological study developed the theory of components. The second volume, "Transitions Between Language and Music" (1998), qualitatively examined their effects, focusing on the creative process between language and music. For the present volume, the transitions have been significantly revised. The case studies and chapters on gestalt therapeutic contact patterns have been omitted, while the theoretical and methodological sections have been condensed and partially further developed. A new addition is the cross-therapeutic perspective of improvisation as a social model, as well as the exploration of the distinguishability of the five effect components. Overall, this results in a textbook.