The Great European Lakes: state of the art -- Hydrothermodynamics of large stratified lakes -- Climatic circulation and the thermal regime of the lakes -- Estimation of the lakes' thermohydrodynamic changes under the impact of regional climate change -- Three-dimensional ecosystem model of a large stratified lake -- Ecosystem models of Lakes Ladoga and Onego -- Estimating potential changes in Lakes Ladoga and Onego under human and climatic impact -- Lake Ladoga and Lake Onego models of fish communities -- Natural resources of Lakes Ladoga and Onego and sustainable development of the region. This book studies the contemporary problems of the Great European Lakes - Ladoga and Onego - on both a regional and a global scale, placing special emphasis on interactions between the limnological and socio-economic environments. Field observations and numerical modeling are used to investigate the responsiveness of both environments to respective impacts, as well as to regional and global climate change. The authors, experts in a wide spectrum of natural and human sciences, use a quantitative approach to assess current and future changes to the interactions between the socio-economic dynamics and limnology of the largest European Lakes compared with the great North American Lakes.