TOM CLANCY has another book out - all's right with the world. Or so goes the collective sigh from millions of mostly male, mostly middle-aged readers.The adjectives come easily when describing Clancy's writing: plausible; compelling; machismo; technical. Each aptly describes the most recent Clancy certain-to-be bestseller. But don't think they suggest a formula as a quick rundown of the book will show. Plausible: However wide-ranging its plot, the very complexity of "The Sum of All Fears," makes it believable. The cold war is over. The Gulf war has come and gone. In its wake, what? Leave it to Clancy to exploit the "peace" in that historically troubled region, the Middle East. And with Clancy, plot equals geopolitics. Plot also stands for subplot, and here in the myriad details of stories within stories Clancy's narrative genius excels. Compelling: Are you lulled into thinking the world is safe for democracy now that the superpowers have backed away from the nuclear brink? Try to ignore the icily convincing near-world-ending catastrophe Clancy serves up. The year is 1997. If you aren't grabbed by Palestinian terrorists, German ultra-radicals in league with unemployed East German secret police and a renegade military scientist, a revenge-seeking Sioux Indian, and a crude Israeli nuclear bomb that might trigger a United States-Soviet Armageddon if it went off, this may not be for you. You're probably not one of the 5 million readers who have bought some 28 million copies of Clancy's books, making him the bestselling American author of the decade. Machismo: There is as much submarine driving in "The Sum of All Fears" as in Clancy's first blockbuster novel, "The Hunt for Red October." Include special forces on covert Central Intelligence Agency missions this time, with full congressional oversight; tank combat in Berlin; Israeli fighter pilots shot out of the sky; and even sex (a first in a Clancy novel). Victorian, of course, with super-hero Jack Ryan eliciting more humor than lust. Ryan has risen in the ranks of the CIA to the deputy director's chair, a long way from his job as instructor at the US Naval Academy, where we first met him five books ago. That his main opponent becomes the president of the United States, whom by the way he is sworn to obey, just compounds interest in how Clancy will get Ryan - an Irish version of Gary Cooper - and the world out of this one. Technical: Clancy's trademark precision on matters of applied science predominates. Can a techno-thriller addict crave anything more, well, technical than the building and deployment of an, albeit crude, hydrogen bomb? From the welding of the winch that will lift it, all the way to computer-guided lasers that wire the bomb's detonator, Clancy has outdone himself with high-tech details. But why should readers not enamored of the Clancy mystique pick up this book, especially if they haven't tried any of his previous ones? Clancy is a one-man war-games institute. In talking with military and intelligence leaders about what they most fear happening on their "watch," and then creating a convincing scenario within which it happens, he sets off alarm bells that will ring in the highest policy arenas of the Western democracies. One afternoon lost in the pages of any of Clancy's books and the machinations of the State Department unfold in a way an entire course in diplomacy would fail to convey. Clancy taps something deep in the American psyche - a national propensity for fair play, as well as adventure and leadership in the international arena. He creates a set of vivid characters, people most of us would know as neighbors, gives them his "God, country, family" values, and sets them in motion.