This volume contains the Proceedings of the Nineteenth JURIX Conference on Legal Knowledge and Information Systems (JURIX 2006). The large number of submissions shows that the interdisciplinary community is still growing and active. This volume again covers a broad range of topics. Argumentation is central to legal reasoning and therefore it is no surprise that researchers have focused on computational theories of argumentation. In this book four papers are dedicated to this topic. Typical to the legal field is the use of written knowledge sources, especially legal sources. These have been subject to AI & Law research for a long time, varying from structuring and accessing legal sources to using natural language processing techniques in order to determine the semantics of language utterances. This book contains four papers on legal sources. Central to AI and consequently to AI & Law are knowledge representation and ontologies. The latter especially are becoming more and more popular due to developments in Semantic Web research. Four papers on these topics can be read in this book. Three papers are included on applications and last but not least, the book contains four short papers on various topics.