In the months leading up to the 1971 Kentucky Derby, Canonero II was an unknown horse with a Venezuelan trainer who spoke only Spanish. The Derby experts laughed when an exercise boy rode the horse out on the track with no saddle or stirrups. But the laughter promptly ended when Canonero II charged to the front from twenty lengths back to win the Derby, followed by a victory at the Preakness Stakes in track record time. In recounting...