A vivid close-up it's not--but with lots of borrowed anecdotes and a general knowledge of the terrain, Baltimore Sun sports columnist Goldstein manages a competent recap of Sugar Ray Leonard's quick-time march from suburban Maryland to Golden Gloves and AAU titles, a 1976 Olympic Gold Medal, and the World Boxing Council welterweight championship. Christened Ray Charles, after the singer, Leonard acquired his nickname from a US boxing team coach who found his flashy style ""sweeter than sugar."" Thanks to kudos from Howard Cosell and his own talent, Sugar Ray was a full-fledged celebrity before leaving the amateur ranks. When he did decide to turn professional, Leonard was astute enough, or lucky enough, to latch onto advisers who treated him as something more than a disposable meal ticket--most prominently, attorney Mike Trainer, a wily negotiator, and Charley Brotman, a PR man who also recruited Angelo Dundee: trainer or manager of 11 world titleholders, including Muhammad Ali. Early on, the brain trust arranged a series of lucrative showcase TV bouts with overmatched palookas--a controversial strategy that paid off handsomely since Leonard polished the skills that enabled him, later, to defeat the likes of Adolpho Viruet, Tony Chiaverini, and Pete Ranzany. What's more, he punched his way to a bankable reputation. ""This kid is. . . like a black Shirley Temple,"" says one promoter. In 1979, Leonard took the WBC welterweight title by knocking out Wilfredo Benitez of Mexico. He lost a 15-round decision and the title to Roberto Duran in a mid-1980 slugfest, but won it back in November when the brawling Panamanian ""retired"" in the middle of the eighth round--a surrender that continues to mystify insiders as well as fans. Just what drives Leonard remains something of a mystery too, but Goldstein's detailed appreciation of his ring career will do as a fill-in for his fans.