Preface: Special Issue on Laboratory and Field Testing of Unsaturated Soils -- Measurement of Matric Suction Using Tensiometric and Axis Translation Techniques -- Indirect Measurement of Suction -- Axis Translation and Negative Water Column Techniques for Suction Control -- Vapour Equilibrium and Osmotic Technique for Suction Control -- Mechanical Testing in Unsaturated Soils -- Laboratory Hydraulic Testing in Unsaturated Soils -- Microstructure Investigation in Unsaturated Soils: A Review with Special Attention to Contribution of Mercury Intrusion Porosimetry and Environmental Scanning Electron Microscopy -- Geoenvironmental Testing -- Field Measurement of Suction, Water Content, and Water Permeability -- Water Balance and Evapotranspiration Monitoring in Geotechnical and Geoenvironmental Engineering -- Monitoring the Performance of Unsaturated Soil Slopes -- Monitoring Large-Scale Tests for Nuclear Waste Disposal. This collection focuses on recent advances in laboratory and field testing of unsaturated soils. Leading researchers from fourteen countries to represent global research in the area of experimental unsaturated soil mechanics have been invited to contribute to this book. Twelve reports are presented dealing with measurement and control of suction and water content, mechanical, hydraulic, and geo-environmental testing, microstructure investigation, and applications of unsaturated soil monitoring to engineering behaviour of geo-structures. The main motivation behind this book is the rapid growth of experimental unsaturated soil mechanics over the last couple of decades. Several innovative laboratory and field techniques have been introduced in mechanical, hydraulic, and geo-environmental testing. However, this information is widely dispersed in journals and conference proceedings and researchers and engineers beginning to work in the field of unsaturated soil mechanics may find it difficult to identify suitable equipment and instrumentation for research or professional purposes. Audience: This volume aims at providing scientists and practitioners with a comprehensive overview of experimental unsaturated soil mechanics.