This volume presents the results of a major international and interdisciplinary study of the mechanisms and consequences of surface water acidification, which is a growing environmental concern. This detailed, long-term study provides an authoritative overview of the chemical process involved in acidification and, in particular, of its biological impact on freshwater life. The Surface Waters Acidification Programme (SWAP) has drawn together for the first time the many facets of this complex phenomenon: the volume includes sections on hydrochemical studies in catchments, catchment process studies, catchment manipulation experiments, chemical processes, paleolimnological studies, biological effects on freshwater life, and modeling studies. The volume finishes with an assessment of SWAP and its conclusions. The results are applicable to all those areas suffering the consequences of acidification, especially in the Northern Temperate Zone. Published on behalf of the Royal Society.