Why are there so few good biographies of horses? Well, never mind, here's one. The main character was an improbable racing champion: undersized, injury prone and ridden by a one-eyed jockey. Yet Seabiscuit captured America's heart, which pounded harder when he faced War Admiral in a showdown in 1938. Seabiscuit won, and Laura Hillenbrand does too with her deft blending of racing lore and social history.