No one would have blamed David Dukes if he had declined reading for Tom Clancy's Rainbow Six. Not only is "Rainbow" a melting pot of secret-agent patois, but the 700-page-plus book version runs at a rampant pace--this despite the usual wealth of Clancy detail. But actor and audio pro Dukes (and the editor responsible for condensing the script onto six hours of tape) handles this daunting task admirably, applying a steady--but not urgent--Everyman's tone and imparting a sense that we're hearing the whole story. Listeners may want more, but will be satiated with this abridged rendition. Dukes also bounces seamlessly among dialects, giving distinct but easy-to-understand voices to Rainbow, a colorful cast of international good guys assembled to save the world from terrorism. The group is led by a sometimes violent but justice-minded ex-CIA agent, John Clark, who is proof that Clancy can paint a dark protagonist as vividly as his good knight, Jack Ryan. But Rainbow Six is an equally bright showcase for reader Dukes, who, like Clark, is bent on providing justice. Dukes's reading gives justice to the abridged form. (Running time: six hours, four cassettes) --Rob McDonald