How are we meant to behave? And how are we to defend whatever answer we give? Morals and Consent grounds our notion of morality in natural evolution, and from that basis, Malcolm Murray shows why contractarianism is a far more viable moral theory than is widely believed. The scope of Morals and Consent has two main parts: theory and application. In his discussion of theory, Murray defends contractarianism by appealing to evolutionary game theory and metaethical analyses. His main argument is that we are not going to find morality as an objective fact in the world, and that instead, we can understand morality as a reciprocal cooperative trait. From this minimal moral architecture, Murray derives his innovative consent principle. The application of the theory, detailing what contractarians can – or ought to – say about moral matters, takes up the greater portion of the work. Murray offers a trenchant examination of what moral constraints we can claim concerning death (abortion, euthanasia, and capital punishment), sex (pornography, prostitution, and sexual assault), beneficence (toward present and future people, animals, and the environment), and liberty (genetic enhancement, organ sales, and torture). By focusing on evolutionary contractarianism and the epistemic justification of our moral claims – or lack thereof – Malcolm Murray's Morals and Consent is a serious advance in the field of applied ethics and fills an important void.