This volume provides a comprehensive coverage of the principal extreme soil ecosystems of natural and anthropogenic origin. Extreme soils oppose chemical or physical limits to colonization by most soil organisms and present the microbiologist with exciting opportunities. Described here are fascinating environments, such as permafrost, saline, arid and geothermal soils, peatlands, subsurface geomaterial rich in sulfidic ore, Martian soils, hydrocarbon-contaminated hot desert and Antarctic soils, as well as fire-impacted, heavy-metal and radionuclide contaminated soils. Those environments lend themselves both to timely descriptions of colonizing organisms and their activities, and to thoughtful examination of community structure and microbial evolution. Extreme soils provide invaluable examples of microbial adaptations in coping with hostile habitats. Being home to a remarkable diversity, they are ideal models for scientific exploration and propose solutions to biotechnology and bioremediation challenges.