When musicians speak of the “form” of a piece of music they are referring to its overall design, plan, pattern, or structure. The nature of musical form is a central concern in Western musical scholarship; systematic writings on form date from the 18th century (Burnham, 2002). This chapter introduces some basic concepts of form in Western tonal music, relates these theoretical constructs to empirical research into the perception and comprehension of larger-scale musical structure, evaluates such research, and offers some directions for future investigation. We will deal only with tonal music, primarily from the Western classical tradition as consideration of nontonal music would require another chapter-length treatment.