Book excerpt: This volume discusses issues related to unsaturated soil mechanics and rock engineering based on technical papers focusing on two important topics in geotechnical engineering: (1) the characterization of unsaturated soils, and (2) the investigation of rock properties. The research studies on unsaturated soils include the characterization techniques of the unsaturated soils. The studies on rock properties include thermo-hydro-mechanical behavior of gypsum rock, soft rocks capacity, role of rock strength in blastability, indirect methods to estimate rock strength, and variations in isotope distributions in Permian rocks. The two broad themes in this collection, as summarized above, are representative of local challenges facing geotechnical engineers in the Middle East, but their contributions can also be extended to other regions of the world. The volume is based on the best contributions to the 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 – The official international congress of the Soil-Structure Interaction Group in Egypt (SSIGE).