Geoffrey Blight completed his PhD at Imperial College, London, on the mechanics of unsaturated soils, under the supervision of the legendary Alan Bishop. His early work, published jointly with Bishop in 1960, 1961 and 1963, provided data that is still being used by new generations of researchers on unsaturated soil behaviour. He soon became interested in residual soils, publishing his first work on unsaturated residual soils in 1963. He served as Chairman of the International Society for Soil Mechanics and Foundation Engineering’s Technical Committee on the Properties of Tropical and Residual Soils from 1994 to 1997 and edited and co-authored the book "Mechanics of Residual Soils", produced during his Chairmanship. Eng-Choon Leong is an Associate Professor at School of Civil Engineering, Nanyang Technological University, Singapore. He obtained his bachelors and masters degrees at the National University of Singapore and a PhD at the University of Western Australia. He has eighteen years of research and teaching experience in Geotechnical Engineering. His research interests are unsaturated soils, residual soils, soil dynamics, foundation engineering and numerical modeling. He has published widely in international journals and conferences. He has extensive experience in laboratory and field testing of saturated and unsaturated soils and in-situ monitoring of residual soil slopes. He has also developed a number of specialized laboratory testing apparatuses and data acquisition systems for field applications. He is also active in consultancy and national technical committees on standards. He has received several awards for his contribution to the accreditation of commercial soil testing laboratories and is a co-author of the ASTM Outstanding Article on the Practice of Geotechnical Engineering awarded in 2006.