From The Preface: This book is intended as an introduction to the elemental factors and processes that operate in lakes, streams, and estuaries as dynamic systems. In seeking to fulfill this intention the aim is primarily two-fold. First, the book attempts to bring into summary some of the major aspects of the knowledge that has been atnassed from the study of inland waters and estuaries by many investigators. Such a study, drawing as it does from geology, hydrology, physics, chemistry, and biology, is obviously vast and complex. In order to appreciate so broad a field it is necessary to view a considerable body of basic factual information.