One of Ernest Hemingway's best stories is just six words long: ''For Sale: Baby shoes. Never used.'' It's hard to imagine a more economical tragedy. He would've loved F.X. Toole, who died before two of his tales became the Oscar-winning film Million Dollar Baby. Not only for his manly bona fides (ex-longshoreman, boxing cut man), but for the haunting simplicity of his prose. Toole traces Dan Cooley, an Eastwood-esque fight trainer with a bum ticker and three dead children, and Chicky Garza, a young Mexican southpaw. Despite some sappy contrivances, Pound for Pound proves that a flurry of emotional jabs can be just as powerful as one knockout punch. Grade: B+