In this book we will think of all the tiles as equally valid options, and we will avoid the concept of a mainstream dominant line (usually considered “progressive”) that implies other secondary or subordinate lines (often viewed as “conservative,” or also as marginal). From the perspective we have at the beginning of the twenty-first century ,moreover, the idea of “progressive” and “conservative” trends in twentieth-century composition seems quite outdated, especially because what was once considered “conservative” by some (that is, writing tonal or pitch-centered music) is one of the preferred options among many of the major present-day composers of various age groups (from emerging composers to well-established masters), and some of the trendstraditionally referred to as “progressive” are of no interest at all to many of the leading
younger composers.