This chapter addresses the cognitive processes that are understood to underlie musical performance in oral and improvising traditions. In relation to music, the idea of an oral tradition refers broadly to musical practices whose means of transmission (of musical ideas and activities—including repertoires, performance conventions, techniques) do not rely on written or printed notation. Improvisation in music, meanwhile, broadly describes the material process and aesthetic consequence where musicians generate organized, meaningful sounds “in the course of performance” (Nettl & Russsell, 1998). In the past, musical improvisation has also been defined primarily through its relation to conventional, scored composition (Nettl, 2005). The title of the chapter thus encompasses a vast array of musical practices, essentially describing all types of performance which are not considered to be part of a highly literate tradition, namely those associated with classical Western art music.