CONFESSIONS OF A FAILED SOUTHERN LADY By Florence King (St. Martin's: $8.95). Florence King's hilarious, often outrageous memoir describes her upbringing by four unlikely characters: a charming, bookish father; a determinedly patrician Virginia grandmother; a devout black woman, and a hoydenish mother who wanted to be the belle of the ballpark. (The only taboo King learned from this nutty group was never to smoke on the street.) A feminist before the term existed, King was equally repulsed by the institutionalized sexism she encountered at the University of Mississippi during the '50s and the vapid co-eds who came to college to get their "M-R-S degree." Like Proust, King learned that a writer must draw on personal experience, however unusual, and her bizarre childhood gave her the courage to subvert conventional mores and become a successful and highly entertaining author.