There is now an increased awareness of the importance of polar regions in the Earth system, as well as their vulnerability to anthropogenic derived change, including of course global climate change. This new edition offers a concise but comprehensive introduction to polar ecology and has been thoroughly revised and updated throughout, providing expanded coverage of marine ecosystems and the impact of humans. It incorporates a detailed comparison of the Arctic and Antarctic systems, with a particular emphasis on the effects of climate change, and describes marine, freshwater, glacial, and terrestrial habitats. This breadth of coverage is unique in the polar biology literature. As with other titles in the Biology of Habitats Series, particular emphasis is placed on the organisms that dominate these extreme environments although pollution, conservation and experimental aspects are also considered. This accessible text is suitable for both senior undergraduate and graduate students taking courses in polar ecology, often as part of a wider marine biology degree program. It will also be of value and use to the many professional ecologists and conservation biologists requiring a concise overview of the topic.