This volume presents cutting-edge research in the field of expert systems and artificial intelligence. The papers collected here are the refereed technical contributions from ES98, the Eighteenth Annual International Conference of the British Computer Society Specialist Group on Expert Systems. They cover a range of innovative developments, including expert systems construction, knowledge base validation and verification, reasoning about device functionality, spatial reasoning, machine learning, case-based reasoning, and data mining.

This fifteenth volume in the Research and Development in Expert Systems series is positioned as essential reading for professionals seeking to stay abreast of advancements in this critical field. The collection offers a deep dive into the technical aspects of expert systems, focusing on novel research and methodologies. Its inclusion of papers on diverse topics such as machine learning, spatial reasoning, and data mining suggests a comprehensive overview of current research directions. The companion volume, Applications and Innovations in Expert Systems VI, covers the more applied aspects, indicating a dual focus on theoretical and practical progress within the expert systems community.