This volume gives a comprehensive documentation of an ecosystem approach in investigating the effects of acid deposition on soils and water. It also contains an analysis of the ecological conditions in an acidified lake prior to liming. It has been considered an advantage to publish as complete a description and analysis of the catchment study as possible in one and the same volume. Experience has shown that such a volume is a valuable reference document which can also be used for future analyses. The present volume contains mainly original publications which should be read as independent contributions. Some papers deviate from this theme. They might be considered as less "exciting" but put into the context of this volume they make a contribution to the understanding of the acidification history and acidification status of the area.