When in 1957 Igor Markevitch and Georges Auric commissioned the 32-year-old Pierre Boulez, fresh from the success of his Marteau sans maître, to write a work for the Société des concerts Lamoureux, the result was an eightminute symphonic torso, Doubles, whose gripping intensity, heroic utterance, and vivid orchestral imagery marked it as potentially one of the composer's most important creative efforts. Announced at its Paris première on 16 March 1958 as the beginning of an ambitious work-inprogress, it was not heard again until January 1964, when the first ten minutes of a revision entitled Figures Doubles Prismes were presented by the Südwestfunk Orchestra in Basle. Instead of adding the expansive second stage of Doubles – which had been mapped out and in part actually composed in particell – the revision opened up the existing first stage by interpolating new episodes of contrasting character. Though the plan of the revision called for a total duration of about 30 minutes (toward which an additional five minutes of music were composed and introduced at the Hague by Het Residentieorkest in 1968), a shift of career focus by the composer in 1971 to conducting and electronic research brought progress on this and several other major projects to an indefinite halt. As a consequence, the intended but still unrealized overall shape of Figures Doubles Prismes, as well as of its forerunner, Doubles, can be appreciated, at least for the time being, only from manuscripts on deposit at Switzerland's Paul Sacher Foundation.