Continuing in its forty-year history of providing students and professionals with a thorough grounding in the science and technology of groundwater hydrology, this third edition has been completely updated to reflect the tremendous changes in the field.  A true essential reference, this book provides a unified presentation of groundwater hydrology, treating fundamental principles, methods and problems encountered in the field as a whole.   Since the earlier editions of this book in 1959 and 1980, the groundwater resource field has made tremendous strides in awareness of the environment, concerns and competition for water supplies, contamination of groundwater, and enhanced regulation of water resources.  This new edition includes the many new developments that have occurred in the groundwater field. Chief among these is the role of computers, not only for organizing data and solving problems, but also in managing groundwater resources on a basin-wide basis for known or anticipated inputs and outputs.  Special focus is placed on modern groundwater modeling methods, including a detailed description of MODFLOW.  Intended Courses: Departments of Civil and Environmental Engineering, Geology, HydrogeologyOne or two term course called Groundwater Hydrology Junior or senior level, or graduate level