Of all the early twentieth century American musical revolutionaries, perhaps composer Henry Cowell wielded the most vivid and far-reaching influence. Born in 1897 to a rural California family, Cowell began to study the violin at age five, though his parents' hopes of creating a prodigy on the instrument remained unfulfilled when the lessons had to be stopped on account of the boy's poor health. After his parents' divorce in 1903, Cowell spent several years traveling around the country visiting relatives with his mother. It was during one such journey in 1908 that he began to write his own music, his first known effort at composition being an unfinished setting of Longfellow's Golden Legend.
Until he began musical studies with Charles Seeger at the University of California at Berkeley in 1914, Cowell remained a basically self-taught musician, as well as a young man who had never spent so much as a day in school in his life. Seeger was impressed by the young Cowell's output — over 100 compositions of varying quality by 1914 — but was much more interested in the young composer's hyper-creative, open-minded musical personality. Free of the often confining attitudes which govern formal musical education, Cowell had come to view any sound as musical substance with which he could work, and his early music owes more to the influence of birdsong, machine noises and folk music than it does to any knowledge of earlier masterworks. In The Tides of Manaunaun, Cowell asks the pianist to use his or her fist, palm, and forearm on the keys of the instrument's bass register to evoke massive tidal waves, an early example of what he called the tone cluster. Cowell used this and similar techniques in many later works, which proved to be highly influential for many of the "sound mass" composers of later decades, including Penderecki, Ligeti, and numerous electronic composers.
However, Seeger felt that without structure and guidelines Cowell would remain an unskilled, if impressively inventive, musician, and he encouraged the young composer to make a rigorous study of traditional harmony and counterpoint. In 1919, at Seeger's suggestion, Cowell finished a systematic treatise on his own music entitled New Musical Resources, in which he discusses new musical techniques, aesthetic directions, and possible alterations to the accepted system of musical notation. Concert appearances throughout North America and Europe during the 1920s earned Cowell countless friends and enemies throughout the musical establishment. Although he had earned the respect of such luminaries as Bartók and Schoenberg, his concerts frequently caused audience riots and invoked the wrath of critics who wondered if Cowell's headstrong independence disguised a lack of true musical craftsmanship. In the Aeolian Harp (1923), for piano, Cowell instructs the pianist to play "inside" the piano by sweeping, scraping, strumming, and muting the strings. The Banshee (1925) applies indeterminacy and graphic notation with instructions for the pianist to play exclusively inside the piano while an assistant holds down the damper pedal. Playing techniques include scraping the strings with a fingernail, and pizzicato effects, all performed in the lowest registers of the instrument, yielding resonant and primarily non-pitched waves of sound.
Later music, such as the Amerind Suite for piano (1939) and the 26 Simultaneous Mosaics (1964) incorporate generous helpings of indeterminacy, though from the 1930s onward, Cowell's compositional language grew increasingly tonal and rhythmically simplified. Cowell died after several years of serious illness.