American composer Morton Feldman is increasingly seen to have been one of the key figures in late-twentieth-century music, with his work exerting a powerful influence into the twenty-first century. At the same time, much about his music remains enigmatic, largely due to long-standing myths about supposedly intuitive or aleatoric working practices. In Composing Ambiguity, Alistair Noble reveals key aspects of Feldman´s musical language as it developed during a crucial period in the early 1950s. Drawing models from primary sources, including Feldman´s musical sketches, he shows that Feldman worked deliberately within a two-dimensional frame, allowing a focus upon the fundamental materials of sounding pitch in time. Beyond this, Feldman´s work is revealed to be essentially concerned with the 12-tone chromatic field, and with the delineation of complexes of simple proportions in ´crystalline´ forms. Through close reading of several important works from the early 1950s, Noble shows that there is a remarkable consistency of compositional method, despite the varied experimental notations used by Feldman at this time. Not only are there direct relations to be found between staff-notated works and grid scores, but much of the language developed by Feldman in this period was still in use even in his late works of the 1980s.