It would be difficult to make the story of Jack the Ripper dull, and Frank Spiering's fluent narrative of the series of murders in 1888 tingles in all the right places. But Spiering's account begins by naming the killer and goes on to trace his movements when not assaulting prostitutes--in asylums, on state tours, in the House of Lords. His Jack, you see, is Albert Victor, called Eddy, Duke of Clarence and elder son of the future Edward VII, a suggestion examined in several books recently but never so firmly insisted upon. Dull from childhood and perverse from adolescence, ignored by his family, infected with syphilis by a prostitute, and associate of a coterie of Cambridge homosexuals, Eddy died a couple of years after the murders. Spiering mutters darkly of poison by the clique which then ran England and had long known the truth but concealed it to protect the throne and their own prerogatives. Indeed, upon a molehill of circumstantial evidence and the undeniably suspicious fact that the official files of the case have been tampered with, Spiering erects if not a mountain then at least a Tower Hill of surmise, extending his slight material to book length with a history of subways and chunks of royal trivia. An eerie book but, at best, an educated guess.