Since publication of the first edition of this text, knowledge of groundwater has advanced and concern about the environment has increased. There have been major droughts and increasing worries over possible long-term water shortages, and suggestions that the climate is being changed by human activities. The second edition covers these topics as they relate to hydrogeology, and is presented in a style intended for the non-specialist reader, with technical terms and mathematical formulae kept to a minimum.;The chapter on water quality has been enlarged to provide more information on chemistry and micro-organisms, and a major new chapter focuses on pollution. The rest of the book has been updated, and contains more on legislation.