Collaboration, for Robert Rauschenberg and Merce Cunningham, began with the arrangement of chairs. In the summer of 1952, when Rauschenberg was 26 and Cunningham was 33, both were living at Black Mountain College, a nontraditional art school in North Carolina that encouraged exchange and experimentation among its students and faculty. One August night, the composer John Cage—Cunningham’s partner—convened an impromptu performance in the dining hall featuring Rauschenberg, Cunningham, and others.