A dozen sports Superstars and how they do it--as confided to, or extracted by, the New York Times prize-winning profile specialist. Keese patiently tries to dig beyond catchphrases like ""concentration,"" ""dedication,"" or ""God-given talent,"" and if he doesn't often strike revelatory pay dirt, details do accrue: the case of rickets that bowed young O. J. Simpson's legs, later seen as essential to the running back's extraordinary balance; the tobacco-wad-tightened cheek of super-batter Rod Carew, which he feels keeps him from squinting or blinking as the pitch bores in; Julius Erving's musical-comedy glove size--13. Anomalies abound: while Jack Nicklaus blots out all awareness of the crowd as he stalks the golf course, Jimmy Connors will interrupt set point to exchange obscenities with a guy in the third row--yet both win. Achievers here tend to come from deprived backgrounds, or stressful ones, but the one thing all seem to have in common--from the gifted, seven-foot-one Kareem Jabbar to the underendowed, myopic Billy Jean King, from brash Muhammad Ali to painfully bashful Bobby Orr--is an ego drive, some constant sense of being better than anyone else and having to prove it. The dozen pieces (reprinted, with some revision, from the Times) offer no startling insights; but, given the subjects and Keese's fluency, none falls totally flat.