The musical world of this century has been dominated, to an extraordinary and unprecedented degree, by the music of the past. Performers play music primarily by long-deceased canonical composers, composers learn their craft by studying the master-works of the past, including the distant past, and scholars devote themselves to studying increasingly ancient musical monuments. The past has never been so powerfully present as in this century. In this historical situation, composers have felt an understandably deep ambivalence toward the masterworks of the past. On the hand, those masterworks inspire admiration, even reverence. At the same time, they also inspire the kind of anxiety that one often feels the presence of powerful, dominating, and intimidating figures. In Stravinsky's phrase: "The artist feels his 'heritage' as the grip of a very strong pincers." The musical tradition, Stravinsky suggests, may provide inspiration, but it also imposes narrow constraints.