In this tale of art, paleontology and discovery, Curtis introduces the masterworks of cave art in France and Spain, visiting Altamira, Lascaux, Les Trois-Freres, Cosquer, Chauvet and others of the almost 350 known caves containing prehistoric art. The celebrated and idosyncratic prehistorian Jean Clottes is one of the heroes in this engaging tale.  (FRN620, $15.95)