A suspenseful, user-friendly account of Microsoft's five-year effort to develop Windows NT (for new technology). Wall Street Journal correspondent Zachary delineates the blood, toil, tears, and sweat required to produce a breakthrough operating system that would not only work on all available personal computers but also allow customers to retain familiar applications programs. Throughout his accessible text, Zachary tries to keep readers in the loop. He provides illuminating reminders of how operating systems (which control a processors basic functions) differ from applications software (the visible programs that retrieve information, maintain databases, prepare documents for printing, and otherwise satisfy human needs). While NT, which reached the marketplace last summer, has yet to achieve critical sales mass, the author leaves little doubt that the $150 million project yielded its creator a host of payoffs: by advancing the state of the networking art, defining the shape of software to come, and giving Microsoft (which last month settled potentially troublesome antitrust charges) an inside track on the interactive information highway. The bulk of the narrative is devoted to anecdotal reportage on how a consequential enterprise managed to harness its varied, volatile, very human resources (many of whom had become independently wealthy by cashing in options on the company's common stock) and meet the self-imposed schedule for NT's introduction. Covered as well are the time and technical tradeoffs made in the course of an undertaking whose final features included more compromises than indisputably correct answers. Nor does the author ignore the human costs of economic and scientific success in his reckoning of the NT balance sheet. An engrossing and instructive case history of programming under fire on the front lines of software technology.