Slow Poison

``To a Southerner, sweet and sad mean the same thing,'' writes Bosworth ( Almost Innocent ), an observation that aptly fits her jilted protagonist, Rory Cade, in love with a man who marries first one of her sisters and then the other, in this family saga rife with alcoholism, insanity, cancer, adultery and traumas related to the war in Vietnam. Set in and around New Orleans, mostly from 1958 to the late '60s, this bittersweet, episodic novel pierces Southern manners and mores with fierce tenderness. Rory's heartthrob, freelance journalist and war correspondent Johnny Killelea, courts ``violence in the name of honor: the Irishman's and the Southerner's constant passion.'' He ricochets from a marriage of convenience to a ``marriage of comfort,'' escaping love. Among Bosworth's memorable characters are Rory's stepmother, reckless belle Aimee Desiree; and Rory's father, Eamon, a charming alcoholic ophthalmologist who sometimes drinks on the job. His plight symbolically echoes Rory's tangled emotions as she sorts through jealousy, pity, rage and affection to see her family and herself with clarity. BOMC alternate. (Mar.)