The highest accolade for a book about philosophy is not that it helps you understand but that it makes you think: the author of Science and Politics in the Ancient World (among others) inhabits his subject, demonstrating, in Aristotelian terms, how experience produced thought, and assessing, in the light of later experience, the validity of his judgments. The book is remarkably unified: Aristotle's life, the climate of ideas, the political circumstances, and his work--the investigations and the formulations--develop apace. Also it is concise and plainly ordered, with the further advantage, for the wary, of an attractive open page, short chapters, and occasional illustrations and maps. Clearly expounded are his dependence on and divergences from Plato, the changes in his own attitudes and ideas, his relation to his Macedonian patrons (especially the ironies of his break with Alexander), his influence on his successors and, later, on those who copied the system rather than the method; at the heart, however, are the writings themselves, treated logically, i.e., as his editors arranged them, beginning with Logic. In comparison, Glanville Downey's Aristotle makes assumptions about his life that are not labelled as speculative, generally switches from individual to ideas, and devotes proportionately more attention to scientific ""discoveries,"" in some cases (e.g., evolution) misleadingly; this is a much more discriminating study.