Abstract. Five overlapping eras or stages can be distinguished in the evolution of music therapy. The first one refers to the historical roots and ethnological sources that have influenced modern meta-theoretical perspectives and practices. The next stage marks the heterogeneous origins of modern music therapy in the 20th century that mirror psychological positions and novel clinical ideas about the healing power of music. The subsequent heyday of music therapeutic models and schools of thought yielded an enormous variety of concepts and methods such as Nordoff–Robbins music therapy, Orff music therapy, analytic music therapy, regulatory music therapy, guided imagery and music, sound work, etc. As music therapy gained in international importance, clinical applications required research on its therapeutic efficacy. According to standards of evidence-based medicine and with regard to clearly defined diagnoses, research on music therapeutic practice was the core of the fourth stage of evolution. The current stage is characterized by the emerging epistemological dissatisfaction with the paradigmatic reductionism of evidence-based medicine and by the strong will to discover the true healing nature of music. This trend has given birth to a wide spectrum of interdisciplinary hermeneutics for novel foundations of music therapy. Epigenetics, neuroplasticity, regulatory and chronobiological sciences, quantum physical philosophies, universal harmonies, spiritual and religious views, and the cultural anthropological phenomenon of esthetics and creativity have become guiding principles. This article should not be regarded as a historical treatise but rather as an attempt to identify theoretical landmarks in the evolution of modern music therapy and to elucidate the evolution of its spirit.
NOLM-based mode-locked Yb-doped fiber laser with wide-spectrum