SWEET DEALS by Brian Lysaght (St. Martin's: $13.95). And where else in the world, pray, do the 'sweet deals' flow like wine? Where else but Tinsel Town, of course, and attorney-turned-crime-novelist Brian Lysaght has a field day prowling the alleys and the glitzy palaces of Los Angeles and Malibu in this fast-paced mystery that starts out deceptively low-key but shortly becomes as complex as a Wilshire Boulevard accountant's cattle/oil drilling tax shelter. Lysaght's protagonist, raffish and streetwise lawyer Ben O'Malley, has a dash of Ross MacDonald's Lew Archer and a dollop of Hammett's Sam Spade in him, but stands very well on his own two feet--no small distinction in a genre where, given Southern California as the setting, these MacDonald-Hammett (and Chandler) comparisons seem inevitable. Teaming up with his friend and partner, Jerome Baird, the initial challenge in "Sweet Deals" seems almost pedestrian: Find the missing husband of the sexy heiress to the Kendall Industries fortune, Anna Bradley. Not so simple, after all, however, as the tangled trail leads to a multimillion-dollar mob laundering operation, fancy-footed double-entry bookkeeping and, of course, murder most foul. Welcome to O'Malley's witty world of Sunset Boulevard hookers, hanky-panky in the movie industry, enough bloodletting to stock a donor bank and multiple bed-hopping in the best Hollywood tradition.