This investigation traces the history and development of music theory in Mexico from the date of the first Mexican treatise available (1776) to the early second half of the nineteenth century (1866). This period of ninety years represents an era of special importance in the development of music theory in Mexico. It was during this time that the old modal system was finally abandoned in favor of the new tonal system and that Mexican authors began to pen music treatises which could be favorably compared with the imported European treatises which were the only authoritative source of instruction for serious musicians in Mexico.

This thesis contributes analyses of two works by Mexican composers: Rayo nocturnal (1989) by Victor Rasgado (b. 1959), and the Cuarteto da do (1988) by Juan Trigos (b. 1965). Although composed according to structuralist principles, a postmodern interpretation is offered. The analytical method applied is based on Allen Forte's set theory, including rhythmic and timbral dimensions that are integral to the conceptions of these works. A survey of modernism and postmodernism in twentieth-century Mexico serves to place these works in their cultural context.