In this book, S. A. Lloyd provides a radical interpretation of Hobbes' laws of nature, revealing them to be not egoistic precepts of personal prudence but rather moral instructions for obtaining the common good. This account of Hobbes' moral philosophy stands in contrast to both divine command and rational choice interpretations. Drawing from the core notion of reciprocity, Lloyd explains Hobbes' system of 'cases in the law of nature' and situates Hobbes' moral philosophy in the broader context of his political philosophy and views on religion. Offering ingenious new arguments, Lloyd defends a reciprocity interpretation of the laws of nature through which humanity's common good is secured.