This incorporates and completes the Robinsons' Nebula-winning novelette of the same name--and fuses two promising ideas. The first is the story of a free-fall dance company--literally free fall, in an orbiting satellite--continuing dance-pioneer Shara Drummond's efforts to open up the possibilities of motion in a weightless environment. The second is a showdown between the human race and a swarm of apparently threatening sentient aliens who communicate through dancing. The two notions ought to reinforce each other; instead they noisily underscore each others' pretensions. The transcendental importance of Shara Drummond's art is belabored in oh-wow prose, and the dancers' confrontations with the aliens are inflated into muiti-decibel cliffhangers involving the fate of the human race. One might wish that the Robinsons--who can write with slick but likable verve--had given each idea a story to itself, more steadily developed and less drowned in claims of significance.