The global scale of alien species invasions is becoming increasingly evident at the beginning of the 21st century. This volume is an attempt to provide an overall picture of aquatic species invasions in Europe. Its geographical scope stretches from Irish waters in the west to the Volga River and the Caspian Sea in the east, and from the Mediterranean Sea in the south up to the Arctic coast of Europe. Not all parts of the continent could be covered equally, as in some countries species invasions are not yet studied. The book represents the array of all major European aquatic systems in the broadest geographical and ecological scope possible, from fully saline seas, semi-enclosed brackish water bodies and coastal lagoons to freshwater lakes, major river systems and waterways. Key objectives include the present status and impacts on economy and environment caused by non-native aquatic species in European waters. Altogether more than 100 scientists from 24 countries have joined together to synthesize the available information on bio-invasions.