This chapter will address key principles of music theory from perspectives which are intended to be accessible to sound designers. It will seek to do so via alternatives to standard Western music notation and more specialist nomenclature, whilst still covering foundational issues in choices of pitch intervals, rhythm, melodic contour, tonal attraction and harmony. In doing so, it will discuss metaphors of musical motion, analogies drawn from other art forms, and principles of musical construction informed by psychoacoustical studies and music cognition.