Advances in automated data collection are creating massive databases and a whole new field, Knowledge Discovery Databases (KDD), has emerged to develop new methods of managing and exploiting them. Geographic Data Mining and Knowledge Discovery is the interrogation of large databases using efficient computational methods. The unique challenges brought about by the storing of massive geographical databases has led to the field of Geographical Knowledge Discovery (GKD). Developed out of contributions to the highly-respected Varenius Project in 1999, this collection addresses the special challenges to be found in knowledge discovery and data mining from geographic databases.