This casual anecdotal introduction to the art of choreography will serve best perhaps as a first book for career-minded young readers. It's hard to imagine an adult ballet-goer who hasn't already picked up most of this information; but there is still value in Miss Walker's coherent and digestible formulation, with its, backstage glimpses of artists at work -- a range of methods and temperaments, from meticulous Petipa's table-load of toy figures to Ashton ""screaming"" at live dancers -- and the overview it gives of a dance's evolution, including budgetary influences, the necessary collaborations, and the problems of criticism. Although she refers chiefly to classical dance, her approach is sufficiently general to apply to all major forms, interpolating history as needed for perspective and pausing along the way to consider systems of dance notation. She gets her enthusiasm across in an agreeably ordinary style, for the most part without pushing; but if she insists on anything, it's sympathy for the poor choreographer, who is inevitably the most dependent and vulnerable of artists. Fifty-plus photos show masters in action with their stars.