The aim of the authors in writing this monograph has been to provide a comprehensive and critical, but personal account of salt glands. Papers on salt glands are scattered through a great many different journals. There is therefore a great need for a synthesis of what is known about salt glands. The means by which salt glands perform their vital function of forming and excreting a concentrated salt solution is of great biological importance in understanding salt and water relations in the cells of all living things. In addition to the basic physiology of salt glands there is consideration of their ecological importance, their interaction with other systems of the body, their role in non-marine birds and reptiles and their evolution. Salt glands have interested biologists from a wide range of disciplines. This book brings together the scattered literature and will be a convenient source of reference to those working in the field, as well as providing information for comparative studies and for teaching purposes.