Hart's book The Concept of Law is often called the main work of legal philosophy of the 20th century. The book provides an in-depth analysis of the most fundamental problems of legal philosophy. Hart's innovative ideas expressed in this book are still extremely influential. Moreover, the entire subsequent development of legal philosophy was largely a reaction to this text, and even Hart's critics inevitably repel this book. Unfortunately, Hart's ideas (like the entire Anglo-Saxon tradition of legal philosophy) are not yet well known to the Russian-speaking reader.