The course of events has diluted the impact of this espionage novel which is set in 1978 and which deals, somewhat implausibly, with a plan to overthrow Fidel Castro. Actually the Soviet-backed plan, designed to fail, is an elaborate cover for a scheme to recover a cache of hidden treasure while, at the same time, embarrassing the United States. Action, centered in the Caribbean, includes side trips to Europe, South America, and Washington D.C., but a plethora of characters, coupled with a clumsy story-line, keeps the book from developing any real momentum. Curiously, the most intriguing aspect of this brew is the character of a former beach-boy actor, (and sometimes C.I.A. agent), now hoping to revive his career by posing for a nude centerfold in Playgirl magazine. His photo-shoot, scheduled for a Caribbean island, is part of the larger "overthrow" plot but its chief interest -- alas, only lightly touched on -- involves the mechanics of photographing the well-endowed anatomy of a male sex-symbol - from Amzon