Characters to watch are assorted Mafia hoods; a passel of eccentrics who live at the Seventy-ninth Street Boat Basin; the regulars at Riley’s saloon—Donovan’s favorite hangout and (perhaps) Clint, Donovan’s ill-tempered snapping turtle. Also on hand are Sgt. T. L. Jefferson, Donovan’s redoubtable assistant, and Sgt. Marcia Barnes, the black undercover policewoman who is his on-again, off-again lover. Here’s another jaunty big city thriller by the author of the much acclaimed Night Rituals.