As the field's principal organizer and leading promoter, one is indebted to Nagel for his energy, enthusiasm, and resourcefulness. This volume is imbued with such qualities. It covers vast territory, insistently counters the skeptics, and develops original schema for evaluating the work of the field. Furthermore, as vintage Nagel, the book is highly structured, with many definitions, lists, and prenamed series of ideas. . . . Nagel is unswervingly...