1“If the beat falls in the right place for mypurposes, " wisecracked the late, great Ruth St. Denis, "it's great music. " The First Lady of the

the course of both dance and theater around the world, was joking, of course, but there was an element of truth in her seeming irreverence. Above all, the dancer requires music that is "danceable, " and the choreographer either seeks out already written music that inspires him to create movements equivalent to sound patterns or he commissions new music to sup-port an already conceived choreographic plan. Ballet masterpieces have emerged in both cate-gories: from George Balanchine's world famous Serenade (set to Tchaikovsky's Serenade in C for String Orchestra), a supreme example of a dance genre that St. Denis named “music visual-izations, " to such great ballet-dramas with spe-cially commissioned scores as Antony Tudor's Undertow, music by William Schuman, an