The book "Experimental Unsaturated Soil Mechanics" is a comprehensive collection of contributions that emerged from the International Conferences on the Mechanics of Unsaturated Soils held in Germany. It aims to discuss and understand the behavior of unsaturated soils in order to improve quality and judgment in engineering applications. The topics addressed include the challenges of adapting new concepts and making them applicable in engineering education. The experimental studies focus on the role of microstructure and geometry in relation to the complex hydro-mechanical behavior of cohesive, frictional materials. Additionally, the relevance of temperature for the constitutive behavior of clays is examined. The contributions also cover modern theoretical and numerical approaches aimed at describing the multifaceted problems of coupled thermo-hydraulic-mechanical-chemical processes, which are significant in various applications such as the disposal of highly toxic waste and the stability of slopes.