Legal Theory, Sources of Law and the Semantic Web is an attempt to construct an integrated conceptual framework for the application-neutral and problem-neutral representation of sources of law using Semantic Web technology and concepts, and some technically straightforward extensions to Semantic Web technology based on established practices found in fielded applications. To construct this framework, the author disentangled some problems that are often mixed up in legal theory and – in extension – legal knowledge representation. The purpose of this framework is to provide a theoretical background for the creation of reusable and maintainable knowledge components representing knowledge of sources of law on the Semantic Web. These components should form a basis for the development for computer applications supporting straightforward, routine decision making problems using traditional methods. This book aims to be a work of ontology: an account of relevant aspects of the knowledge domain of law from the perspective of a legal knowledge engineer interested in sources of law. One cannot however say that the result of this work is an ontology: this book presents a mix of design principles, design patterns for knowledge representation in OWL DL and ontology fragments.