At their best, Laymon's cackling horrors (The Stake, 1991; Night Visions 7, 1989) are the nastiest around--sleek, black- humored, skirting (if not slipping over) the edge of pornoviolence. Here, though, he injects them into a floundering picaresque historical about Jack the Ripper--set partly in the Old West- -resulting in his only seriously dull book yet. Even Laymon's usual thrumming prose is missing here, replaced by a faux-plucky narration (``It wasn't a job I could walk away from''; ``Right then I vowed to save her'') by 15-year-old Londoner Trevor Bentley, who, one dark-and-stormy night in 1988, goes searching for a bobby to corral the lout who's beaten his mom. Wandering the streets, Trevor is attacked by thugs who strip him; seeking clothes, he breaks into an apartment but hides under the bed when the occupant returns--a whore accompanied by none other than the Ripper, who mutilates the woman while the boy cowers inches below: a wicked beginning that Laymon soon squanders. Trevor follows ``the fiend'' only to be shanghaied--along with luscious young Trudy Armitage--aboard the Armitage family yacht, which the Ripper has pirated, aiming to sail to the fresh killing-ground of America. Sundry tortures, mostly of Trudy, make the voyage pass quickly; arriving in the US, the Ripper rips Trudy and escapes, trailed by Trevor, who loses his prey but is taken in by a retired general and his daughter, who tutors the boy in sex. Long months later, reading of savage murders in Tombstone, Trevor rides the rails west, where he takes up with outlaws, dallies with yet another pretty girl, and, at last, confronts the Ripper in a blood- spouting finale. Laymon dedicates this meandering mistake to his agent, who, he says, suggested ``an English setting...so this book is your fault.'' Okay--but Laymon himself should have known better. And next time, with luck, will.