Jockey Shoemaker is a winner. Indeed, with nearly 9,000 victories and well over $100 million in purses to his credit, the ageless wonder (still active at 57) is arguably the best rider in Thoroughbred racing history. His ramshackle autobiography, though, is a horse of a different color. With the inept assistance of Daily Racing Form columnist Nagler, Shoemaker jogs through a hit-or-miss account of the seemingly effortless course that took him from stable hand to legendary status in the sport of kings. There have been far more ups than downs in a remarkable career that dates back to 1949. Unfortunately, the thrice-married author and his collaborator seldom vary the pace, much less the tone, of the narrative. Thus, notable triumphs in major stakes events and individual honors are accorded the same relentlessly laconic treatment as personal setbacks--such as a costly divorce from wife #2 or a couple of debilitating injuries. On occasion, the deadpan style produces memorable howlers, e.g., ""Waxahachie didn't have much speed, which proved a real handicap."" But the discontinuous text is not wholly with reward for diehard railbirds. To illustrate, Shoemaker offers a partial apologia for the still notorious 1957 Kentucky Derby, in which he mistook the finish line and probably cost Gallant Man the race. Owing to the 11th-hour nature of the assignment, Shoemaker's agent was unable to book him another mount on the Derby Day card, and he hadn't ridden for over a year at Churchill Downs--whose wire is one-sixteenth of a mile closer to the first turn than at most other courses. Still, a few bright moments of this sort apart, the Shoe's reminiscences are up the track and out of the money. There are to be pictures (not seen).