This book constitutes the refereed proceedings of the 4th International Conference on Logic Programming and Nonmonotonic Reasoning, LPNMR '97, held in Dagstuhl Castle, Germany, in July 1997.The volume presents 19 revised regular papers together with 10 system descriptions and five abstracts of invited presentations. The papers included report state-of-the-art research and development in the interdisciplinary area of logic programming and logical foundations of artificial intelligence.