Once again, Tom Clancy manages to add new twists to the alternate U.S. history he initiated in The Hunt for Red October. In The Sum of All Fears, the center of conflict is the perpetual hot spot the Mideast, where a nuclear weapon falls into the hands of terrorists just as peace seems possible. Clancy realistically paints an almost unthinkable scenario--the bomb is planted on American soil in the midst of an escalation in tension with the Soviet Union; the terrorists hope to rekindle cold war animosity and prevent reconciliation between Israelis and Palestinians. Despite such a dramatic story line, Clancy doesn't neglect the individuals who drive his tale. Jack Ryan's problems are as much domestic as they are part of the international crisis that is the ostensible narrative: National Security Director Elizabeth Elliot has the president's ear, and she has convinced him that Ryan's ethics are questionable. She hints at marital infidelity and an insider-trading scandal. Of course, both accusations are false, but her arguments have enough evidence behind them (e.g. some photographs of an innocent embrace with a friend) to cause a strain in the Ryans' marriage and a flurry of media attention. While "Mr. Clark" tracks the terrorists, he also provides some needed intelligence to heal the Ryan family. The Sum of All Fears is the stuff of nightmares but contains enough verisimilitude to terrify sober minds. Ryan has matured into a complex protagonist as Clancy's writing, too, has matured. Ryan is plagued by stress and self-doubts that test even his dauntless moral compass and make him a more interesting subject for readers' attention. Those fascinated by military hardware, from nuclear submarines to atomic weapons, will find almost enough here to start their own army. And Clancy's understanding of international politics seems chillingly correct. --Patrick O'Kelley