Henry Cowell's theater piece Fanati has been shrouded in historical mystery. Described as a "Prologue and Nine Scenes of a 'Fantastic Satire' " for singers, piano, and percussion, Fanati was based on a text by Ralph Emerson Welles. In 1935, when it was given its only performance, Henry Cowell had the reputation, both in Europe and the United States, above all as a pianist, famous for playing his own works, which were often based on tone clusters--chords of various sizes based on seconds, especially minor seconds. (These chords he had orchestrated in such pieces as Synchrony, but they were-and are still--considered particularly pianistic.) Fanati is, however, of a different order. It has existed primarily through hearsay and memory because no parts survive among the corpus of Cowell's manuscripts. Since Cowell had written out the parts to virtually all his pieces up to that time, the score to Fanati has long been presumed lost. But there is another explanation for the absence of parts. In the course of my research, I made contact with Florence Welles, the widow of Fanati's librettist. Now her recollections and new source materials change the conception of the work from "lost" to "found." That is to say, she told me that there had never been a set of parts for Fanati, that it had been a largely improvised work. Therefore the work was not "lost." This essay is largely based on her recollections of Fanati, in which she, the only surviving performer from its one and only production, contributed both manuscripts and recollections that have allowed me to reconstruct Cowell's original conception. It should be said from the outset, moreover, that Fanati holds a special place in Cowell's oeuvre. For, although pieces that are based on improvisation are commonplace today, at the time Fanati was composed, they were not. Thus the piece is prophetic, both within Cowell's corpus of work, pointing toward two pieces Cowell composed for Martha Graham, Sarabande (1937) and Deep Song (1937), Cowell's later mosaic