A must-read for any and all law students (along with Dworkin's "Law's Empire"). Both are pre-eminent jurisprudence scholars of the 20th century.

Hart takes apart the legal positivism of Austin and acknowledges some validity in natural law theory. But Hart fails to connect the "minimum content of natural law" with his analysis of a "rule of recongition" that allows a legal system to exist.

Hart's critique of Austin's legal positivism is right on and rightly consigns it to the dust bin as a way of explaining all manifestations of the phenomenon of law. Law as a threat backed up by force simply cannot explain contracts, wills, and trusts. The law doesn't just threaten people, it also empowers them. Positivism also fails to acknowledge the "internal" aspect of legal rules as well as failing to give an account of how law is recognized, clarified, and changed. Hart posits a "rule of recongition" to take care of this. Hart acknowledges a "minimum content of natural law" that explains the purpose of law as responding to certain human needs (bodily vulnerability, limited altruism, etc.). This gave rise to the revival of natural law theory in Anglophone jurisprudence in the 20th century. But Hart just kind of sticks the natural law chapter in his book without saying how it connects to the rest of what he says about legal rules and systems. Look at Finnis' Natural Law and Natural Rights for the "extension" of Hart's project.

One of the highest achievements in the history of jurisprudence. Simple to read, complex to thoroughly grasp, written in clear prose but full of ideas. Previous familiarity with Kelsen and Austin should prove helpful to extract the most out of this book. You can follow it by reading Dworkin and Bobbio (sadly unavailable in English - his Teoria della norma giuridica and Teoria dell'ordenamento giuridico are as obligatory as Kelsen and Hart).

Even though it is a work of legal positivism, it contains one of the best analyses of natural law and ethics I have ever read. This is, much more than the elements it's most famous for (the distinction between primary and secondary rules), what makes The Concept of Law shine.

The postscript, also sold separetely at Amazon, is included in this second edition of the book.

Hart insists that there are many differen kinds of rules - he only 'elucidetes social rules' -but he also accepts that not all legal rules are social rules. What then are they? The foundation of his account of a social rule is an aspect of the form of life (vide Wittgenstein) underlying the use of language - but it is life without the multiplicity of activity at any one time and without conflict.