This book is an updated and revised edition of Fundamentals of Legal Argumentation published in 1999. It discusses new developments that have taken place in the past 15 years in research of legal argumentation, legal justification and legal interpretation, as well as the implications of these new developments for the theory of legal argumentation. Almost every chapter has been revised and updated, and the chapters include discussions of recent studies, major additions on topical issues, new perspectives, and new developments in several theoretical areas. Examples of these additions are discussions of recent developments in such areas as Habermas' theory, MacCormick's theory, Alexy's theory, Artificial Intelligence and law, and the pragma-dialectical theory of legal argumentation. Furthermore it provides an extensive and systematic overview of approaches and studies of legal argumentation in the context of legal justification in various legal systems and countries that have been important for the development of research of legal argumentation. The book contains a discussion of influential theories that conceive the law and legal justification as argumentative activity. From different disciplinary and theoretical angles it addresses such topics as the institutional characteristics of the law and the relation between general standards for moral discussions and legal standards such as the Rule of Law. It discusses patterns of legal justification in the context of different types of problems in the application of the law and it describes rules for rational legal discussions. The combination of the sound basis of the first edition and the discussions of new developments make this new edition an up-to-date and comprehensive survey of the various theoretical influences which have informed the study of legal argumentation. It discusses salient backgrounds to this field as well as major approaches and trends in the contemporary research. It surveys the relevant theoretical factors both from various continental law traditions and common law countries.