If you think you wouldn't raise your skirts for a rakish legend about the purifying powers of a unicorn's horn, then maybe you aren't a 15th-century serving girl under the sway of a velvet-tongued court painter of ill repute. In keeping with her bestselling Girl with a Pearl Earring, and its Edwardian-era follow-up, Falling Angels, Tracy Chevalier's tale of artistic creation and late-medieval amours, The Lady and the Unicorn is a subtle study in social power and the conflicts between love and duty. Nicolas des Innocents has been commissioned by the Parisian nobleman Jean Le Viste to design a series of large tapestries for his great hall (in real life, the famous Lady and the Unicorn cycle, now in Paris's Musee National du Moyen-Age Thermes de Cluny). While Nicolas is measuring the walls, he meets a beautiful girl who turns out to be Jean Le Viste's daughter. Their passion is impossible for their world--so forbidden, given their class differences, that its only avenue of expression turn