Lake Ladoga is the largest lake in Europe and, with its surface of 17,891 km2 and volume of 837 km3, it ranks among the top fifteen of the world's freshwater bodies. The ecological condition of Lake Ladoga is of concern to several million people living in its surroundings. There is evidence of water quality degradation and gradual eutrophication of the lake during the past decades; on the other hand, pollution control measures have improved the situation in many of the most polluted sites near industrial effluent sources. The first international Lake Ladoga Symposium was held in St. Petersburg on 22-26 November, 1993. The symposium was attended by 160 scientists, and about half of the papers presented at the symposium have been edited for this book. The contributions are grouped under the following headings: Present state of Lake Ladoga; Hydrodynamics of Lake Ladoga and other large water bodies; Water quality and pollution; Ecological studies of Lake Ladoga biota; History of Lake Ladoga and rates of change in its environment; Research methods for large lakes. Besides providing up-to-date information on the state of the lake, the papers deal with studies of many other large lakes of the cold-temperature zone and the general problems and methods of large lake research. Furthermore, the book is a source of reference to the voluminous Russian limnological literature.