A nicely paced testament to the pleasure and pain of being a world-class runner at distances ranging from a mile through 5,000 meters. Liquori, a successful competitor for more than a decade, appreciates not only the price but also the value of his accomplishments on and off the track. The last high-school miler to break four minutes (3:59.8 in 1967), he is the American record-holder at two miles and 5,000 meters; he also has run the fifth fastest mile in history. Now he's a commercial success as well: co-owner of the Athletic Attic, a fast-growing chain of sporting-goods stores, and a well-paid commentator for ABC's Wide World of Sports. The brash, individualistic Liquori, who still competes at the international level, characterizes himself as more racer than runner, meaning that he has concentrated on establishing a winning record rather than setting attention-gathering time records. He has his say, too, on offbeat subjects like sex and the embarrassing urgencies of elimination that often strike long-distance runners in mid-race. For runners and their fans, the inside track on an obsessive pursuit.