Microbiological examination of extreme environments has revealed many new prokaryotes. Extreme environment is uninhabitable by most of the organisms where extremes of heat or cold, pH, salinity, pressure, and even radiation occurs. Extreme environments are inhabited by diverse populations of microorganisms, the extremophiles. Several classes of extremophiles are recognized in microbiology. Halophiles are organisms that require high NaCl concentrations for their growth and metabolism. Extremophiles are of interest to both basic and applied biology. The book on “Halobacteria in Cape Comorin and metal remediation” is my research work done through laboratory experiments. This book introduces the diversity of halophilic archaebacterial species, especially members of halobacteriaceae in the Cape Comorin coast and associated salt pans. The biodiversity of both halobacterial microbes and total heterotrophic organisms were enumerated and factors affecting their growth were determined. Further, metal toxicity studies and kinetics reveals their useful role in metal bioremediation.