The psycho-acoustic role played by sound and music is well- known to mankind, right from the days of our ancestors who hunted animals and lived in caves for their existence. The archaeological findings of flutes and drums, made of bones and skins of those animals hunted stand as a mute witness in museums around the world. The pre-Vedic and Vedic Indians had carved out a practical system, which used concepts and practices relating to acoustics and psychoacoustics. The birth of the new discipline ‘music therapy’ is a post-War American phenomenon, born in its unsung bivouacs. This idea caught fire soon, as people from various disciplines (music, musicology, medicine, psychiatry, psychology, rehabilitation, yoga and spiritualism) started pouring in to experiment at it. As a consequence, what we call ‘music therapy’ is no longer a 'close-your-eyes-and listen-to-music' subject, but is a full discipline incorporating tenets of arts and science, brain and heart, thoughts and feelings, expectations and experiences, illness and well-being and above all the past and the present.. A Dictionary of Music Therapy, adorning your hand now, is the first of its kind in the world music therapy literature. It makes an attempt to tackle this multi-disciplinary subject to cater to the day-to-day needs of a scholar or a practitioner in music therapy from all parts and cultures of the world.