Mark McGwire and Sammy Sosa are unlikely superstars. Sosa grew up in a Dominican slum, his family so poor he had to use a milk carton for a fielder's glove. McGwire was drafted as a pitcher and didn't move to first base till he was in college. So how did the two of them manage to smash Roger Maris's record for home runs in a single season? Exciting photos and clear, dramatic text make these easy-reading biographies a winning lineup for the very youngest fans.