Fifteen-year-old Jack Walsh is elevated from head exercise rider to “bug boy,” or apprentice jockey, after another jockey is severely injured during a race. The Saratoga Race Course in 1934 is vividly realized in Jack’s believable first-person, present-tense narration, as he navigates the dangers success brings. A gangster pressures him to deliberately lose a big race, a wealthy young female bookie energetically seduces him, his father arrives back on the scene after abandoning him as a child to a physically and sexually abusive horse trainer, and he endures the constant, graphically portrayed imperative to lose large amounts of weight quickly in order to be light enough to race. Luper is at his best depicting races that are both thrilling and plausible as Jack strategizes his way past more experienced but less clever riders. Occasional violence, sexuality and Jack’s extreme weight-loss efforts make this a more suitable read for older teens, who will find themselves thundering through the home stretch in order to discover whether Jack will win, place or show in this first-rate novel. (Historical fiction. 13 & up)