This volume contains the Proceedings of the Second International Workshop on Unsaturated Soils, which was held in Anacapri, Italy, from 23 to 25 June 2004. This meeting was organized by the Department of Geotechnical Engineering of the University of Naples Federico II and the Department of Mechanical and Structural Engineering of the University of Trento, under the auspices of the Technical Committee on Unsaturated Soils (TC6) of the ISSMGE and the Associazione Geotecnica Italiana (AGI). In line with the spirit of the first workshop in 2000, post-graduate and post-doctoral researchers from different universities were invited to present their work. This book contains peer-reviewed papers on unsaturated soils, particularly new developments in laboratory testing, experimental data on compacted and natural soils and constitutive and numerical modelling of unsaturated soil behaviour.