Eating disorders, she argues, are as much a biochemical addiction as a psychological disorder.

While her fluent prose occasionally seems too off-the-cuff, for all its apparent spontaneity her narrative supplies a wealth of information from varied psychologists and theorists, and she sensitively traces the crazy quilt of overlapping motivations and influences behind her disease. Hornbacher's unblinking testimonial has the nuance and vividness of an accomplished novel, and is evenhanded enough to shake the whiff of solipsism that often clings to tales of personal woe. Repeatedly hospitalized during high school, she studied briefly at American University while also working as a journalist, until the final crisis, when her weight dropped to 52 pounds and doctors gave her a week to live.

The only child of the troubled union between a former theater director and his actress-turned-school-administrator wife, Hornbacher was bulimic by the age of nine and anorexic by 15, finding in masochistic self-denial a seemingly dependable-and quickly indispensable-way to control the anxiety that wracked her. ''Eating disorders have the centripetal force of black holes,'' states Hornbacher, 23, midway through this riveting, startlingly assured account of her bout with anorexia and bulimia, a decade-long struggle that brought her to the brink of death at age 18 and left her with chronic physical ailments.

Wasted by marya hornbacher