Charles Mingus’s audiences never knew quite what they were going to get, and this kept them coming. Mingus, the bassist, composer, and bandleader who reached the height of his fame in the mid-1960s, was notoriously mercurial. He was known to fire and rehire band members over the course of a set, and was once fired himself for chasing a trombonist across the stage with an axe. His reactions to noisy crowds ranged from announcing, “Isaac Stern doesn’t have to put up with this shit,” to ordering his band to read books onstage. His music, which drew omnivorously on the blues, gospel, Dixieland, Duke Ellington, bebop, and classical music, among much else, was similarly unpredictable. It blurred the boundaries between improvisation and composition, often ignoring standard form, and was famous for its rapid shifts in mood and tempo.