Conspiracy suspense Ã la Ludlum. . . and Hitchcock. . . and everybody else--with a few fresh touches, a potpourri of agreeably corny devices, a surprisingly literate manner, and a nice steady pace (until the disappointing last 150 pages). The opening chapters are the best here, verging on tongue-in-cheek, as N.Y. book editor Jay Thompson angrily discovers the body of ex-CIA Director Allen Roland (an apparent suicide-by-hanging); Roland, you see, had gotten a huge advance for his supposedly scandalous memoirs but delivered a totally tame manuscript, thus cooking Thompson's goose. When Roland's literary agent also seems to commit suicide, however, Thompson and journalist pal Harriet Mitchell figure that Roland was killed because of something in that manuscript; and a posthumous note from Roland then leads Thompson to Dartmouth prof T. O. K. Smith, an old OSS type who deciphers the code-message in the manuscript--warnings about a ""Zodiac file"" hidden at Roland's Virginia home! But what is Zodiac? And why is a sadistic ex-CIA hitman called ""Cyclops"" killing everyone who knows anything about it (including Smith, via a phone-triggered bomb)? Well, even when Thompson finds the Zodiac file (a near-fatal encounter with the villains), all he learns is that Zodiac has something to do with Mexico, illegal aliens, four code-named biggies, and a private hunting preserve in New Hampshire. So Thompson, now believing (implausibly) that bedmate Harriet (ex-mistress to the VP) is part of the conspiracy, heads for that well-guarded preserve--with the bad guys in pursuit. And the last, slow 150 pages are Thompson's physical ordeal there (attacked by animals, thrown from a plane, in hand-to-hand combat, etc.) as the conspiracy is revealed: it's actually fairly small-potatoes stuff, involving a fake international incident that will swing the upcoming election the President's way. Nor is this ho-hum Big Secret the only problem here: Hyman seems uncertain whether he wants to be serious (Harriet's sexual problems) or cartoony; Thompson unconvincingly turns into a superman warrior; and a subplot about a legendary agent (""The Chameleon"") who's trying to stop Zodiac is merely distracting. Still, when Hyman is just having fun--with hidden files and ciphers, with bald borrowings from North by Northwest, with the publishing biz--he does a nice, twisty job. And readers who are willing to suspend a whole lot of disbelief will find this a lively, kitchen-sink thriller--with none of Ludlum's mindless urgency, but with far more style and variety.