Even by tack-room standards, stony-faced Willie Shoemaker, 32, seems a little smaller than life. Standing on tiptoe, he is barely 5 ft. tall and weighs only 98 Ibs. But Willie casts a considerable shadow. In 15 years of booting thoroughbreds around the nation's racetracks, he has won more than 4,850 races, and his mounts have earned almost $31 million.
Millionaires beg like mendicants for Shoemaker's services. Trainers claim that a race horse improves by two or three lengths simply by having Willie on its back. Bettors lucky enough to back him on one of his hot days (eight times in...