Major parts of the oceans and lands of our planet are permanently, or temporarily, exposed to temperatures below 10 C. Microorganisms, plants and animals living under these conditions have adapted to their environments in such a way that metabolic processes, reproduction and survival strategies are optimal for their natural biotopes. This book presents the most recent knowledge of the ecology and the physiology of cold-adapted microorganisms, plants and animals, and explains the mechanisms of cold-adaptation on the enzymatic and molecular level, including results from the first crystal structures of enzymes of cold-adapted organisms.