Schoenberg, who taught Webern and Berg, is the well-known inventor of the 12-tone system (Josef Hauer independently invented one on separate principles about the same time). Schoenberg was, amazingly, a self-taught musician, whose Harmonienlehre ("Theory of Harmony") is still studied for the breadth of its understanding of the deepest meaning of structure in music. For all its theoretical underpinning, Schoenberg's music is most often dramatic in a romantic way, at the same time leaping to the horizons of pitch in its melodies and, through fragmentation and "Klangfarbenmelodie" (sound-color-melody), creating an angular, "modern" sound in its rhythm and unique orchestration. Schoenberg's earlier and more romantic scores are Verklärte Nacht ("Transfigured Night") for string sextet or orchestra; Pelleas und Melisande (no relation to Debussy's work); and Gurrelieder, which is Mahleresque in texture; all are conceived on a sweeping scale of interior emotion. The early Chamber Symphony combines this style with the angular style that would appear in Schoenberg's violin and piano concertos of the 30s. The first of Schoenberg's works in which tonality is completely absent is the song "Du lehnst wider eine Silberweide" ("You Lean against a White Willow") from The Book of the Hanging Gardens (1907). Following this came the brilliant Five Pieces for Orchestra, op. 16 (1909), with its entirely new approach to orchestration (the suspended chords and color-melody of "Summer Morning by a Lake"); the Piano Music, opp. 11 & 19; and Pierrot Lunaire; all of which completely changed the sound of symphonic, chamber, and piano music. The later expressionistic pieces followed -- Variations for Orchestra, Quartets for Strings nos. 3-4, Von Heute auf Morgen ("From Today until Tomorrow"), and Die glückliche Hand ("The Fortunate Hand"). The culmination of these efforts was his masterpiece, the opera Moses und Aron, which shares with the early work Friede auf Erden ("Peace on Earth") the idea of music being a vehicle for the expression of philosophy. His pleas for humanity during and following the horrors of WWII are contained in A Survivor from Warsaw and the Ode to Napoleon Bonaparte. ~ Blue Gene Tyranny, All Music Guide