The atmosphere of innovation and experimentation in the 1960s was not lost on Leonard Bernstein. His advocacy for the Mahler symphonies, for instance, was highly influential to a generation of composers excited by Mahler’s stylistic heterogeneity. Indeed, one of the best-known examples, Luciano Berio’s Sinfonia, was dedicated to Bernstein and a New York Philharmonic commission. Bernstein also collaborated with two other mavericks of that decade: the pianist Glenn Gould and the composer John Cage. With the former, Bernstein led a much-understood but controversial performance of the Brahms first piano concerto; with the latter, he created a programme with the Philharmonic about what he called aleatoric music, including a performance of Cage’s indeterminate work Atlas Eclipticalis. These encounters were of immense importance to all three artists.