Composer; born in Menlo Park, Calif. Largely self-taught as pianist and composer, in his teens he gravitated to radical musical experiments including his trademark use of tone-cluster harmony. From the 1920s he pursued an international career as composer, concert promoter, and pianist, specializing in his own and others' "ultra-modern" music; he also taught and wrote books including the 1919 New Musical Resources, and in 1927 founded the historic New Music Quarterly. In his own music, progressive ideas appear alongside traditional material; his works include 20 symphonies.