Merce Cunningham reached the age of 75 in 1994, an age at which many creative artists are content to rest on their laurels, or at least to leave behind whatever controversies they may have caused during their careers. No so Cunningham. In the first place, his 70s have been a time of intense creativity in which he has choreographed as many as four new works a year. Cunningham is a strongly committed as ever to the discovery of new ways of moving and...