A slangy, overwrought history--lamentably lacking in perspective--of MCI, largest of the upstart enterprises that have been chipping away at AT&T's dominant position in long-distance telecommunications since the early 1960's. Granted access to corporate records and personnel, Kahaner seems co-opted by his sources. At any rate, the narrowly focused David-and-Goliath account he offers credits the Bell System (which retains a 90% share of market, versus MCI's 5-6%) with scarcely any redeeming values. Barely acknowledged as well are scores of MCI/AT&T competitors, including GTE's Sprint and U.S. Telecom. Almost as distracting as the text's us-against-them bias is an egregiously graceless style, e.g., ""While dating a woman whose businessman father was so rich he couldn't see straight, Brian (Thompson) decided that business was the way to go."" Kahaner includes lengthy rundowns on many of MCI's legal battles with the Bell System (whose 1984 breakup he erroneously attributes to the company's efforts). All but lost in the shuffle, unfortunately, is the landmark Carterfone decision that in 1968 opened the nation's telephone network to so-called foreign attachments. Equally troublesome is Kahaner's reluctance (or inability) to draw appropriate conclusions from his own reporting. To illustrate, once past the billion-dollar mark in annual revenues, the hang-loose folks who run MCI seem to have begun using the highhanded tactics for which they still deprecate AT&T against lighter-weight challengers. Management has also exhibited a remarkable capacity for blundering into deceptively congruent ventures (electronic mail and paging devices, for example), which tie up corporate resources without providing payoffs. The upbeat subtitle notwithstanding, MCI's victories may prove Pyrrhic. Owing to the capital-intensive nature of the telecommunications business, plus rapid advances in long-line voice and data technology, the company faces a decidedly iffy future. In fact, IBM now holds a substantial minority interest in MCI, which has been selling off a number of ancillary assets in an effort to maintain its independence--and momentum. A wrong number.