In 1952, John Cage shocked audiences with 4'33", his compositional ode to the ironic power of silence. From Cage's minimalism to Chris Burden's radical performance art two decades later (in one piece he had himself shot), the post-war American avant-garde shattered the divide between low and high art, between artist and audience. They changed the cultural landscape. Feast of Excess is an engaging and accessible portrait of "The New Sensibility,"...