Groundwater Hydrology is a comprehensive textbook designed to teach the fundamental principles of underground water and how to solve modern water engineering problems. The book’s scope treats principles, methods, and realistic case studies as a unified whole, covering groundwater movement, well construction, expanded coverage of chemical contamination, and modern computer modeling—including the industry-standard USGS MODFLOW model. Its primary contribution is providing an up-to-date, highly practical guide that combines science and technology, serving as an essential tool for students and professionals working to manage and protect vital groundwater resources today.