E. Michael Bridges is a soil scientist who has specialized in the geography, genesis and degradation of soils. He holds the degrees of BSc and MSc from the University of Sheffield and the degree of PhD in Physical Geography from the University of Wales. He is a Fellow of the Institute of Professional Soil Scientists and of the Royal Geographical Society of London. His career began as a soil surveyor with the Soil Survey of England and Wales and continued as a member of the academic staff of the University of Wales, Swansea. His final appointment was with the International Soil Reference and Information Centre (ISRIC) at Wageningen in The Netherlands. Dr Bridges has made over 120 contributions to scientific journals and has edited or co-edited several books including Principles and Applications of Soil Geography (Longman) and written The Soils and Land Use o f the Area North o f Derby (Soil Survey of Great Britain), Surveying Derelict Land (Oxford University Press), and World Soils (Cambridge University Press). He also contributed to the preparation of the World Reference Base for Soil Resources (Acco, Leuven) and co-edited an accompanying Atlas. Ian D. Hannam has had a 30-year career in many aspects of soil conservation and natural resource management. He is currently Manager o f Soil and Vegetation in the Department of Land and Water Conservation, New South Wales, Australia. He is an Appointive Vice President of the World Association of Soil and Water Conservation (Australasia). He obtained his Dip Agr Sci from the Charles Sturt University, BA and M Litt from the University of New England and PhD in Environmental Law from the Macquarie University. Dr Hannam is a world authority on the law and policy of soil conservation and is a member of the IUCN's Commission on Environmental Law. He is currently leading the investigation into the development of frameworks for international and national environmental law instruments on sustainable soil. He is widely published in the subjects of land eValuatin, soil conservation field research, and national and international environmental law and policy. He advises governments on environmental law and policy reform for sustainable land management and now lectures on this topic throughout the world. L. Roel Oldeman has been Director of the International Soil Reference and Information Centre at Wageningen in The Netherlands since 1992. He holds the Irdegree in Tropical Soils from the Wageningen Agricultural University, The Netherlands, and the PhD degree from the University of Hawaii, USA, in Tropical Soils and Agronomy. The first nine years of his professional career were spent as an agroclimatologist in Indonesia, followed by a three-year assignment at the International Rice Research Institute (IRRI), Los Banos, The Philippines, where, as a visiting scientist, he coordinated a United Nations Development Programme/World Meteorology Organization project on rice-weather relationships. In late 1985 he returned to The Netherlands to join the International Soil Reference and Information Centre (ISRIC). A special assignment' in Madagascar for IRRI/USAID led to the preparation of an agroclimatic map of Madagascar, published in 1990. He also coordinated the United Nations Environment Programme (UNEP) project for the Global Assessment of the Status of Human-Induced Soil Degradation (GLASOD), also published in 1990. In several recent papers and articles Dr Oldeman has expressed concern about the deteriorating condition of the soil resource and the threat this poses to food security, particularly in the developing countries of the world. Frits W.T. Penning de Vries graduated from the Nijmegen University, The Netherlands, as a biologist, and presented his PhD thesis in plant physiology at the Wageningen Agricultural University in 1973 on the subject of quantifying respiration in crops. After that, he participated in, and organized training programmes on, crop physiology and crop simulation, and took part in multidisciplinary research programmes on pasture production in West Africa, tree production in the USA, and rice production systems in Asia. Over 80 research papers resulted from his work, and he (co-)edited more than 10 books. He was editor-in-chief of the Kluwer Series Systems Approaches for Sustainable Agricultural Development, and editor of several journals, including Agricultural Systems (current). He was director of research of IBSRAM from 1997 to March 2001, and since then joined the International Water Management Institute, where research on land and water is his main task. Sara J. Scherr is an agricultural and natural resource economist, who specializes in the economics and policy of land and forest management in tropical developing countries, especially in environmentally fragile lands. She is presently a Fellow of Forest Trends, and Adjunct Professor at the Agricultural and Resource Economics Department of the University of Maryland, College Park, USA. She previously worked as a Principal Researcher at the International Center for Research in Agroforestry (ICRAF) in Nairobi, Kenya, and as a Research Fellow at the International Food Policy Research Institute (IFPRI) in Washington, D.C. She has published over 100 scientific papers and 8 books. Her current research focuses on agroforestry adoption, policies to promote environmental services in agricultural landscapes, policies to reduce poverty through natural resource conservation, impacts of land degradation and rehabilitation, and local institutions for natural resource management. She received her BA at the Wellesley College in Massachusetts, and her MSc and PhD in International Economics at the Cornell University in New York. Samran Sombatpanit had been a staff member of the Land Development Department, Bangkok, for 36 years until he retired in 1999. He has experience in research and extension in the field of acid sulphate soils, peaty soils and sloping land. He founded the Soil and Water Conservation Forum-the predecessor of the Soil and Water Conservation Society of Thailand-in 1980 and served as its first president. He is at present a member of the Board of Directors of the International Soil Conservation Organization (ISCO), the Deputy President of the World Association of Soil and Water Conservation (WASWC) and a member of the Management Group of the World Overview of Conservation Approaches and Technologies (WOCAT) Project. He received his BSc (Soils) from Kasetsart University, Bangkok, and Agrlie in Soil Chemistry and Soil Fertility from the Swedish Agricultural University at Uppsala. He has earlier edited Soil Conservation Extension: From Concepts to Adoption, and co-edited Incentives' in Soil Conservation: From Theory to Practice, both published by the Science Publishers, Inc., USA.
