A cynical mixture of assassination, extortion, and general all-purpose political corruption, The Royce Prospect charts the presidential career of the third-richest man in the world. Allen Royce, oil-magnate extraordinaire, will do anything, including allowing the destruction of entire nations, to extend his family's financial empire. Jake Stoner, a political columnist and former husband of Royce's sister, attempts to prevent Royce from succeeding in his nefarious deeds. Despite a surface appearance of action and suspense, this novel fails. The plot lacks originality or cohesion and culminates in one of the more disappointing fictional cliches, and the characters are forgettable. Some readers may remember this prolific author of popular fiction from such books as Aspen, Acapulco, Fire Island, et al., published in the 1970s, but this latest novel is not recommended. --Elsa Pendleton, Boeing Com puter Support Svces., Ridgecrest, Cal.