Geotechnical investigation, which is usually implemented to obtain baseline information of ground and groundwater, is the focus of this book. Authored by practitioner and academic who is extensively involved in geotechnical ground investigations over four continents, this book covers both large scale preliminary ground investigation and intrusive detailed investigation, as well as specialized in-situ testing to obtain advanced geotechnical parameters of soils. Both surface and borehole geophysical methods used in geotechnical investigation, including methods of sampling and tools to obtain good quality soil samples are also discussed and presented in the book. Written for advanced undergraduate and graduate students, researchers and practitioners in the fields of geotechnical engineering, geoenvironmental engineering, and ground investigation, the book also provides guidelines on presenting factual geotechnical data and preparing factual reports.