The Merce Cunningham Dance Company rolls through Chicago for the final time on Friday and Saturday, performing at the Harris Theater as part of its Legacy Tour. (It began last February and winds up on New Year’s Eve in New York, with tickets going for a mere ten bucks.) Cunningham, one the greatest choreographers of modern dance, died in 2009 at the age of 90, and one of the notable achievements of his long career was to use some of the most radical, forward-looking music ever made in his performances. Of course, Cunningham’s partner was brilliant composer and thinker John Cage, so he was never at a loss for resources. Cage was a longtime musical director of the company—which officially began in 1953—and after his death the role was taken over by David Tudor and Takehisa Kosugi. The company’s list of repertory composers is staggering, a kind of who’s who of the avant-garde: Maryanne Amacher, Robert Ashley, Pierre Boulez, Earle Brown, Brian Eno, Pierre Henry, Annea Lockwood, Gordon Mumma, Morton Feldman, Pauline Oliveros, LaMonte Young, and many others. A huge number of great players from the worlds of jazz, improvisation, and experimental music worked with the company, including Jim O’Rourke, Christian Marclay, Marina Rosenfeld, Keith Rowe, and William Winant.