Preface; Introduction; Part I. Biology and Philosophy: An Overview: Introduction; 1. The place of biology in Aristotle's philosophy D. M. Balme; 2. Aristotle's biological universe: an overview Montgomery Furth; 3. Empirical research in Aristotle's biology G. E. R. Lloyd; Part II. Definition and Demonstration: Theory and Practice: Introduction; 4. Aristotle's use of division and differentiae D. M. Balme; 5. Divide and explain: the Posterior Analytics in practice James G. Lennox; 6. Definition and scientific method in Aristotle's Posterior Analytics and Generation of Animals Robert Bolton; 7. First principles in Aristotle's Parts of Animals Allan Gotthelf; Part III. Teleology and Necessity in Nature: Introduction; 8. Aristotle's conception of final causality Allan Gotthelf; 9. Hypothetical necessity and natural teleology John M. Cooper; 10. Teleology and necessity D. M. Balme; Part IV. Metaphysical Themes: Introduction; 11. Aristotle's biology was not essentialist D. M. Balme; 12. Logical difference and biological difference: the unity of Aristotle's thought Pierre Pellegrin; 13. Kinds, forms of kinds, and the more and the less in Aristotle's biology James G. Lennox; 14. Animals and other beings in Aristotle L. A. Kosman; 15. Aristotle on bodies, matter, and potentiality Cynthia A. Freeland; 16. Aristotle on the place of mind in nature William Charlton; Index locorum; General index.