This edited volume on Arctic, Antarctic and sub-polar microbiology is designed to introduce this fascinating field to a wide range of microbiologists and environmental scientists. Polar microbiology is a fast-growing field that can tell us much about the fundamentals of life on earth and the microbial contributions and consequences to such important global environmental issues as warming earth, ozone depletion, and elemental cycling. Polar microbial communities are considered important analogues for astrobiology investigations looking for life on other very cold solar system bodies.