The class act of the urban thriller, Colin Harrison in The Havana Room explains the mysteries of Manhattan real estate and the city's restaurant business -- reasons enough to read the novel -- and also offers a vivid portrait of a once-prosperous lawyer at loose ends (busted marriage, fired from plush firm, dirty Brooks Brothers shirts; oh, lord, it's painful!) who freely admits, ''I scare much more easily than before. I freak more easily. I take threats very seriously.'' Threatened, freaked, he gets involved in a shady real estate deal, cuddles with a sexy middle-aged woman (but not the corpse he finds frozen to a bulldozer), and contemplates eating fugu fish. That's right: potentially poisonous fugu fish. Come on. Are you in the bookstore yet?