 This article has two central objectives. First, it aims to identify the defining features of natural law moral theory. Second, it aims to identify some of the main theoretical options that natural law theorists face in formulating a precise view within the constraints set by these defining features and some of the difficulties for each of these options. It will not, however, attempt to recount the history of the development of natural law thought. (For a very helpful detailed history of natural law thought up to the beginning of the modern period, see Crowe 1977. For a very helpful detailed history of natural law thought in the modern period, see Haakonssen 1996. For an article-length recap of the entire history of natural law thought, see Haakonssen 1992.)