The book "Microbial Ecology of Extreme Environments" offers a comprehensive examination of microbial lifestyles and biochemical adaptations in extreme environments. It summarizes the latest findings in this research field and serves as a valuable reference for future studies. The authors present innovative ideas for the biotechnological and commercial use of microbiomes found in extreme habitats. The chapters on viruses expand the informative content of the book. It takes a vertical journey through the microbial biosphere, covering cold, hot, extremely salty, and high-pressure environments. From the depths of the ocean to polar deserts and the clouds in the atmosphere, the diversity of microbial life in various habitats is described and thoroughly analyzed. The book also discusses potential biotechnological applications and aims to serve as a useful reference for researchers looking to start a research program in extreme microbiology.