Every head of state in business or politics who believes it's lonely at the top can take refuge in this broad look at the travails of leadership by the director of the Center for Leadership and Change Management at the University of Pennsylvania's Wharton School. Useem picks nine leaders from different realms of business, public service and government, and focuses on one critical decision that each had to make. For NASA flight director Eugene Kranz, it was guiding a crippled Apollo 13 back to Earth. For El Salvador's President Alfredo Cristiani, it was bringing an end to his country's civil war. The stories are packed with detail, and some include charts and tabular matter as well. Useem does an excellent job of underscoring the lessons that would-be leaders should take away from his profiles. For example, as part of the Apollo 13 story, "When both speed and precision count, sharing information and keeping everybody's eye on both goals simultaneously are essential for achieving both," he says. Commenting on John Gutfreund's loss of Salomon Inc. ("one of Wall Street's richest companies"), Useem writes, "Inaction can be as damaging to leadership as inept action." These lessons are brought home again, often in the same words, in the Conclusion and the Leader's Guide, a listing of nostrums for aspiring managers. 32 photos. (Sept.) (Publishers Weekly)