The Southern Oceans including Antarctic regions are peculiar and very sensitive water biotopes, where animal life and species interrelations are only poorly investigated. Especially the influence of parasites on their host species needs intensive consideration in times of global warming and worldwide pollution. Both factors may influence the finely balanced interrelationships between parasites and endangered hosts especially in specialized regions such as Antarctica. Before this background the present book offers a broad spectrum of important parasite-host interrelations in times of ecosystem changes written by experienced and renown international specialists.