This book constitutes the proceedings of the 19th Annual German Conference on Artificial Intelligence, KI-95, held in Bielefeld in September 1995. The volume opens with full versions of four invited papers devoted to the topic "From Intelligence Models to Intelligent Systems". The main part of the book consists of 17 refereed full papers carefully relected by the program committee; these papers are organized in sections on knowledge organization and optimization, logic and reasoning, nonmonotonicity, action and change, and spatial reasoning.