This book presents four extended essays that are rooted in the growing interdisciplinary field of applied musicology, in which music theory - in particular, the zygonic conjecture - is used to inform thinking in the domains of music psychology, music education and music therapy research. It is essential reading for academics and postgraduate students working in these fields. The topics covered include a new study on the emergence of musical abilities in the early years, using the Sounds of Intent framework of musical development; an exploration of how the Sounds of Intent model can be extended to map how people with learning difficulties engage in creative multisensory activities; an investigation of the expectations generated on hearing a piece of music more than once evolve in cognition, using evidence from a musical savant; and a report on the effect on listeners of repeated exposure to a novel melody. Data are drawn from the findings of postgraduate and postdoctoral projects. It is hoped that this exciting new work will act as a catalyst in the emerging field of applied musicological research, and bring recognition to a group of new young academics.