It is somewhat ironic that the Minimalist movement, which has been hailed by many as a welcome return to simplicity, has arguably provoked more terminological confusion than any other musical movement in the twentieth century. What is Minimalism when applied to music? Is it an adequate term to describe this movement or does it have misleading connotations? Does it show parallels with its counterpart in the visual arts? In what context did it arise? These are all frequently asked questions which this chapter will attempt to answer. Many of the attempts to define Minimalism thus far have only focused on obvious surface features without probing deeper into its musical core. The result of all this is that after thirty years of Minimalist scholarship we have a widespread acceptance of a term which is still not fully understood. In order to address this situation comprehensively, this chapter will be divided into two distinct but nonetheless intrinsically linked sections. The first section will focus on the inadequacy of ‘Minimalism' as a descriptive term when applied to music. Ultimately, however, it must be conceded that it is too late for a name change and we must accept what is now a common currency in musicological terms. Since this is the case and we are dealing with an accepted term, an understanding of the generic essence of the music itself and an awareness of the term’s limitations is necessary. This is the argument which will comprise the second half of this chapter. I will examine the nucleus of this music and put forward a definition which will adequately describe the music of La Monte Young, Terry Riley, Steve Reich and Philip Glass, the four composers most associated with the movement. This definition of Minimalism will place it in a context which also considers the post-Cagean and post-war Serial movements. Finally, I will define the distinction between ‘Classic’ and ‘Post’ Minimalism which I feel is necessary to cater for the influences of Minimalism in more recent compositional trends.