8 oz.; 287 pages; PB Good ++ Unread cover wear name inside aged. Threshold-a secret weapon so powerful it could paralyze a nation's warning systems, leaving it utterly vulnerable to nuclear strike. And only the Russians had it. The only defense: steal the key to it-with the help of a daring covert agent, a curvaceous electronics expert, and a pair of Russian aces who might or might not be willing to defect.