This book looks at hydrogeology. In this fourth edition there are five new case histories: The Dakota Aquifer ; fractures in sedimentary rocks - Newark Basin ; faults as aquifer boundaries ; desert hydrology - Azraq Basin, Jordan ; and the use of multiple geophysical techniques to determine the extend and thickness of a critical confining layer. It also includes: Excel-based projects in the water chemistry and ground water modelling chapters ; and analysis sections in select chapters, directing the students to a problem or issue that employs critical thinking and problem solving techniques.