The form of my Symphony in One Movement is a synthetic treatment of the four-movement classical symphony. It is based on three themes of the initial Allegro non troppo, which retain throughout the work their fundamental character. The Allegro opens with the usual exposition of a main theme, a more lyrical second theme, and a closing theme. After a brief development of the three themes, instead of the customary recapitulation, the first theme, in diminution forms the basis of a scherzo section (Vivace). The second theme (oboe over muted strings) then appears in augmentation, in an extended Andante tranquillo. An intense crescendo introduces the finale, which is a short passacaglia based on the first theme (introduced by the violoncelli and contra-bassi), over which, together with figures from other themes, the closing theme is woven, thus serving as a recapitulation for the entire symphony.
-- Samuel Barber