This proceedings contains 38 papers that advance understanding of measuring, characterizing, and predicting the properties, behavior, and performance of unsaturated materials typically used in geotechnical engineering practice. The materials addressed include coarse-grained soils, compacted soils, geotextiles, loess, residual soils, shales, spoil fill, and swelling and expansive soils. These unsaturated materials are characterized with respect to soil-water characteristic curves, hydraulic conductivity, shear strength, and/or stress-strain properties. Both static and dynamic loading conditions are considered. Advances in the state of the art with respect to both laboratory and field measurements of unsaturated soil properties are included. Finally, predictions of unsaturated soil properties and their behavior with respect to specific applications, such as landfill liners and covers, heave of slabs on grade, and the bearing capacity of foundations on or in unsaturated soils are addressed.