In this book emphasis is placed upon the physiological and ecological problems of life in estuaries and the close links between these usually divergent approaches to biology. The majority of the examples quoted are from the British Isles but also include some references to Northern Europe and the rest of the world. The introductory chapter deals with the structure of estuaries and the main features of an estuarine environment. Succeeding chapters consider the problems and limited success experienced by both plants and animals in the colonization of estuaries, life in hypersaline lagoons and brackish seas, and the effects which mankind has had on estuaries and their inhabitants. The final chapter outlines a number of possible projects which could be undertaken and presents a comprehensive reading list. This book will be particularly suitable for sixth-form, training college, and first-year university students and fills a present gap in the ecological literature at this level.