An insider's appreciation of 18 basketball players whose distinctive skills and noteworthy rivalries helped mold the modern professional game. Holzman--currently, courtside mentor of the New York Knicks--diplomatically confines his dozen profiles to non-Knicks: Bob Cousy, Bill Russell, Jerry West, Wilt Chamberlain, Oscar Robertson, John Havlicek, Rick Barry, Elvin Hayes, Dave Cowens, Julius Erring, Kareem Abdul-Jabbar, and Bill Walton. His choice of significant matchups, however, includes Chamberlain vs. Russell, Dave DeBusschere vs. Gus Johnson, Earl Monroe vs. Walt Frazier, Bill Bradley vs. Havlicek, and Willis Reed vs. Abdul-Jabbar. Holzman has a keen eye for the foibles as well as the accomplishments of his superstars. He notes, for example, that the mini-wars between Russell, a defensive specialist, and Chamberlain, ""the greatest single offensive force to come into pro basketball,"" generally resulted in statistical standoffs. In eight of nine playoff series, however, the Celtics beat Wilt's team. Holzman attributes the embarrassing margin in large part to Chamberlain's inability to handle the media pressure that built once his reputation as a ""loser"" was established. Hayes, a born-again Christian of whom much was expected, suffered similar agonies until the Baltimore Bullets had a championship season in 1977-78. And the same fate may be in store for box-office bait Julius Erving, unless the 76ers get their act together. Complementing the first-rate reportage are some grand yarns, including the intelligence that Cousy, following his final game at Boston Garden, missed his first shot at a toll-booth basket on the Mass. Turnpike. Even the howlers are ingratiating, as when Holzman, trying to account for Robertson's on-court talents, observes: ""He was born with a basketball in his mouth, I guess."" For devotees of the numbers game, there's an appendix providing rundowns on the regular-season and playoff records compiled by Holzman's handful. On the whole, the veteran coach has come up with a winning combination.