Editing Henry Cowell (section)

===New music and first tours===
Beginning in the early 1920s, Cowell toured widely in North America and [[Europe]] as a pianist, with the financial aid of his former tutors — playing his own experimental works, seminal explorations of [[atonality]], [[polytonality]], [[polyrhythm]]s, and non-Western [[musical mode|modes]].<ref name=r26>Rischitelli, p. 26</ref><ref name=lat/> He gave his debut recital in New York, toured through [[France]] and [[Germany]], and became the first American musician to visit the [[Soviet Union]],<ref name=jul/> with many of these concerts sparking large uproars and protests.<ref name=hick190>Hicks, p. 190</ref> It was on one of these tours that in 1923, his friend [[Richard Buhlig]] introduced Cowell to young pianist [[Grete Sultan]] in Berlin. They worked closely together — an aspect vital to Sultan's personal and artistic development. Cowell later made such an impression with his tone cluster technique that prominent European composers [[Béla Bartók]] and [[Alban Berg]] requested his permission to adopt it.<ref>Sachs, p. 121</ref><ref>Rischitelli, p. 27</ref> [[File:Henry Cowell playing the piano.jpg|thumb|left|upright 1.2|Cowell playing the piano, demonstrating his "forearm" technique by slamming down with his right arm on the middle register, {{circa|1920s}}]] In a letter addressed to his friend on January 10, 1924, Cowell wrote, "I kicked up quite a stir in London and Berlin, and had some very good, and some very bad notices from both places."<ref>Rischitelli, p. 34</ref> A new method advanced by Cowell during this period, in pieces such as ''Aeolian Harp'' (1923) and ''Fairy Answer'' (1929), was what he dubbed "[[string piano]]" — rather than using the keys to play, the pianist reaches inside the instrument and plucks, sweeps, and otherwise manipulates the strings directly. Cowell's endeavors with string piano techniques were the primary inspiration for John Cage's development of the [[prepared piano]].<ref>Nicholls (1998), p. 523</ref> In early chamber music pieces, such as ''Quartet Romantic'' (1915–17) and ''Quartet Euphometric'' (1916–19 {{Audio|Cowell-Quartet Euphometric.ogg|listen}}), Cowell pioneered a compositional approach he called "rhythm-harmony": "Both quartets are [[polyphony|polyphonic]], and each melodic strand has its own rhythm," he explained. "Even the [[Canon (music)|canon]] in the first movement of the ''Romantic'' has different note-lengths for each voice."<ref>Oja (1998), p. 4</ref>

In 1919, Cowell began writing ''New Musical Resources'', which was finally published after extensive revision in 1930. In the book, Cowell discussed the variety of innovative [[rhythm]]ic and harmonic concepts he used in his compositions (and others that were still entirely speculative).<ref>Rischitelli, pp. 6-7</ref> He talks about [[Harmonic series (music)|harmonic series]] and "the influence [it] has exerted on music throughout its history, how many musical materials of all ages are related to it, and how, by various means of applying its principles in many different manners, a large palette of musical materials can be assembled." It would have a powerful effect on the American [[experimental music|musical avant-garde]] for decades after. [[John Cage]] hand-copied the book and later studied Cowell, and [[Conlon Nancarrow]] would refer to it years later as having "the most influence of anything I've ever read in music."<ref name=gann43>Gann, p. 43</ref>