MAGGIE IS 31 YEARS OLD, single and solvent. As the perfect middle child of eccentric parents, Maggie has allowed herself to become a cool observer rather than an engaged participant in her own life. Only when she accepts her roommate Rebecca's invitation to complete a magazine quiz does Maggie's outlook begin to change. She answers the question "Are you happy?" with "no," a response that threatens to shave decades off her life. In fact, the quiz predicts that Maggie has only three months to live.     Maggie's sisters--stormy Lucy, who has just returned from Rome pregnant and unmarried, and self-absorbed Janet, who has found contentment in a single daily pill--distract Maggie from seeking her own measure of happiness. But when it appears that Lucy will lose custody of her newborn child, Maggie is forced into action. On the road with baby Philip, Maggie is helped by a succession of women who speed her, like a heroine on an old-fashioned quest, on her way. Is Maggie's journey the route to happiness, or is happiness simply too mysterious, too elusive to lend itself to capture?     Anne Giardini has intuitive storytelling ability, an affinity for the interior voice and a warm affection for her fallible, lovable characters. The Sad Truth About Happiness is a witty and deeply felt novel that explores the vexing problems of family, love, work, friendship, loyalty, the ingredients of happiness and sorrow, and our purpose and role in the world.