"Preface Soils are dynamic living systems that constitute a vital part of the environment. The soil- environment is the engine that provides the base or platform for human sustenance--food, shelter, and clothing. Food production, forestry, and mineral extraction are some of the life-support activities that depend on soils--in addition to their utility in constructed facilities. All the activities associated with soils require knowledge of their properties and their behaviour under various scenarios and requirements. Studies on soils and their characteristics, properties, and behaviour have been conducted in many different fields of science and engineering. Considerable progress has been made over the past 50 years in our understanding of soil behaviour, and especially in regard to the over-riding physicochemical control of soil behaviour. Much of the progress has been due to (a) the concerted focussed research efforts of researchers, and the exchange and acceptance of ideas and information between different disciplines such as soil engineering, soil science, mineralogy, microbiology, engineering geology, etc., and (b) the trans-disciplinary and multidisciplinary research studies mounted by these different disciplines. There has been heightened understanding of the significant roles of geologic origin and regional controls on the nature, properties, and response performance of soils"--