The characteristics of logic programming languages both necessitate and motivate innovative approaches in the areas of user environments and programming tools. The Tenth Workshop on Logic Programming Environments provided a forum for researchers, developers, programmers, and users to exchange ideas and results on all aspects of environments for logic programming. Contributions coming from Europe, the USA, Australia and Japan addressed debugging (4x), vizualization, graphical spreadsheets, and automated documentation. Coming from a different background, Clinton Jeffery, invited speaker, presented a monitoring environment for C which, we hope, was inspiring for the logic programming community.A special thanks to Enrico Pontelli, ICLP'99 workshop coordinator. Thanks also to Francisco Bueno, Manuel Carro, Erwan Jahier, Sarah Mallet, Julio Marino, and Olivier Ridoux who helped with paper reviewing.