This book constitutes the refereed proceedings of the 20th Annual German Conference on Artificial Intelligence, KI-96, held in Dresden, Germany, in September 1996. The book presents three invited papers together with 23 revised full research papers, nine posters and four systems demonstrations. All contributions were carefully selected from a larger number of excellent submissions, of which a considerable part had been submitted from abroad. The papers address many subareas of AI; however, there is a certain focus on new develpments in theorem proving, knowledge representation, and reasoning.