An incredible book for the same audience as Joseph H. Mazo's Dance is a Contact Sport (1974), but with less boyish enthusiasm and a very different sort of grasp. What Gruen has done is to assemble scores of interviews with central figures going back to the original Ballet Russe. They span a whole tradition -- a tradition that relies to an exceptional degree on face-to-face confrontations. We have always wanted to know more about the chemistry-cum-mechanics of dancing, the dynamics of all those mixed-up and incestuous personalities; but that would call ideally for some sort of holographic medium that would print everybody's autobiography simultaneously. Gruen goes about as far as is presently feasible in that direction. . . beginning with Serge Lifar, snagged at a Cannes gala Hommage a Diaghilev, something about him now seeming permanently stunned. In a way this book is a ghostly beginning that provides a most uncomfortable sense of history; but soon the fascination of a multiple viewpoint sets in and personalities emerge in heightened third-dimension. This, one feels, is the way it really is -- and still all within living memory. Some who speak are Rosella Hightower, Dame Margot, Danilova, Markova and a Coward-esque Anton Dolin, Nureyev, Bejart, and Ailey -- a whale of a scope, with interests as diverse as Mr. Balanchine's wives and Arthur Mitchell's project in Harlem. The interest in fact seems just about inexhaustible, and the audience we'd guess to be big.