About the Author: Malcolm G. Anderson, is founder and Editor-in-Chief of Hydrological Processes, the international research journal published by Wiley. Professor Anderson has longstanding research interests in the fields of numerical hydrology and geotechnical model development for landslide prediction. He has held full year appointments as a Senior Research Hydrologist, for the U.S. Corps Engineers Waterways Experiment Station, USA and the Geotechnical Control Office, Hong Kong. Des E. Walling is with the Department of Geography at the University of Exeter in the UK.