In Defense of Legal Positivism is an uncompromising defence of legal positivism that insists on the separability of law and morality. After distinguishing among three facets of morality, Matthew Kramer explores a variety of ways in which law has been perceived as integrally connected to each of those facets.

Some of the chapters pose arguments against other major theorists such as David Lyons, Lon Fuller, Joseph Raz, Michael Detmold, Ronald Dworkin, Nigel Simmonds, John Finnis, Philip Soper, neil McCormick, gerald Postema, Stephen Perry, and Michael Moore, while others extend rather than defend legal positivism; they refine the insights of legal positivism and develop the implications of those insights in strikingly novel directions. The book concludes with a detailed discussion of the obligation to obey the lae- a discussion that highlights the strengths of legal positivism in the domain of political philosophy as much as in the domain of jurisprudence.