A Discussion Review of Philip Kitcher, Vaulting Ambition, MIT Press, Cambridge, Massachusetts, 1985. xi + 455 pp., $25.00.The Problem and Context of "Vaulting Ambition: Sociobiology and the Quest for Human Nature" -Philip Kitcher has written a thorough work that will satisfy critics of sociobiology, while at the same time he hopes to advance the methodological basis of a legitimate science of biology and behavior. This task is accomplished using the analytic skills of a wellinformed philosopher of science. Kitcher is as much at home discussing the complexities of John Maynard Smith's game theory calculations, employed to explain competition and the limits and constraints thereof (evolutionary stable strategies), as he is the intricacies of the technical distinctions of prominent modern moral philosophers employed to tackle problems that arise in discussions of freedom and determinism. In his own words (personal communication), Kitcher uses the Lockean metaphor of an underlaborer to describe his project in Vaulting Ambition. As underlaborer he identifies and removes the debris of faulty thinking by making precise distinctions and analyzing arguments. Kitcher's tack is like that of Socrates' whose probing questions and cross examination expose to Euthyphro that his statements are premature and that his inchoate ideas have far-reaching implications. For Kitcher the value of Socratic questioning is not to destroy, in this case the sociobiological program, but to clarify our ideas, reminiscent of C. S. Peirce, about simple yet fundamental concepts in the logic of scientific explanation. The arguments presented in the book are stimulating not in the sense of offering creative and imaginative perspectives laying new brick and mortar to the sociobiological archetechtonic. The book is stimulating however because Kitcher's arguments will force researchers in sociobiology to look reflexively and critically at the axiomatic foundations of their hypotheses, models, and explanations. Accordingly, an implicit agenda is established in Vaulting Ambition concerning the methodological foundations for an improved science of sociobiology that can be thought of as paradigmatic, in the Kuhnian sense, commanding rigorous analysis and subsequent modification.