The aim of the textbook is to provide students with a guide to the basic theoretical questions of law. It is up to legal theory to reveal common principles and traditions beyond local particularisms. A bridge should be built between the study of positive law and the study of legal theory. Too often these fields are studied separately as if opposed to each other. But practice without theory is blind while theory without practice is useless. The author has devoted separate chapters to the important topics - nature of law, major legal systems, sources of law, legal relations, legal liability, interpretation of law, law and morality, law and justice. The textbook is intended primarily for foreign students which attend courses of legal theory at the law schools in the Czech Republic. It can be also useful for Czech students which would like to extend their knowledge of English legal terminology.