A (fictitious) master plan for 16th-century megalomaniacs sets the game afoot in this reasonably interesting, though overlong, thriller by first-time author Rabb. The how-to-do-it book is called On Supremacy, and it has legs, long ones. It turns out that what pushed hot buttons in 1531 is still catnip to would-be world-dominators today. Back then, bits and pieces of the book were shown to Pope Clement VII by an ambitious Swiss monk named Eisenreich, whose brainchild it was and who was hoping for patronage and employment. Clement was impressed. In fact, unnerved. For the sake of maintaining the status quo, he ordered the treatise burned, but since Eisenreich had by then hidden it well, the Pope decided to bum him instead. Now, as the millennium is about to end, On Supremacy seems to have surfaced, and a sinister cabal finds it an ideal blueprint for effecting chaos, knowing that chaos will lead to disorientation, which will lead to terror, which will result finally in despair, ever the fertile breeding ground for New Orders of every description. Thus, the stage is set for a basic global thriller. Among the familiar ingredients: (1) highly placed moles, (2) clandestine, licensed-to-kill agents, (3) brilliant but batty archvillains, (4) brilliant but nerdy computer whizzes, and the obligatory (6) hyper-realism (""Washington, February 26, 12:45"", etc.). Give Rabb credit for one departure, though, as he rings some lively changes on the customary hero-heroine relationship, allowing agent Sarah Trent and Professor Xander Jaspers to embody a refreshing role-reversal. Sarah's the one licensed to kill, while Xander looks to her for protection. Not that he's wimpish. It's just that the anarchic, kill-or-be-killed world he all of a sudden finds himself in is completely alien to him. But not to her. She, as she phlegmatically informs him, is good at chaos. In a book, say, 75 pages thinner, Rabb's intriguing odd couple might have been enough to carry the day.