How can we separate the dancer from the dance? Vaslav Nijinsky's art was a vanishing act, and his mystique depended on gestures that lasted only a second, like his leap through a window in "The Spectre of a Rose," or the slight but scandalous quivering of his thighs that mimed ejaculation when, performing Debussy's "Afternoon of a Faun," he rubbed himself against the captured drapery of a fleeing nymph. Offstage he was stolid — as blockish as Stravinsky's wooden Petrushka or, according to the sniffy socialites who patronized the Ballets Russes, as unimpressive as a shop assistant, a plumber's apprentice or a stable lad. After his mental breakdown, he spent decades in a state of blank-eyed mutism, interrupted only by inappropriate giggling fits.

NIJINSKY: A Life, by Lucy Moore. Profile, 2013, 320 pp., £25 (hardcover)

Lucy Moore retells the familiar story engagingly, with due deference to Richard Buckle's completer account, but she can't help expressing her bafflement about a man whose art denied him a verbal outlet while requiring him to work through a series of mysterious physical metamorphoses.