Eliot Asinof's newest baseball hero left tiny Gandee, Missouri, as John Clyde Cagle Jr., a hard-throwing lefthander who had pitched a perfect game in high school. Now he returns in triumph as the legendary "Black Jack," superstar of the Los Angeles Dodgers, a stoic, menacing mound demon with a Fu Manchu moustache and a 106-mile-per-hour fastball. In a nationally televised event that, like everything else in his life, is precisely orchestrated...