Whether they are exposed to extremes of heat, cold, or buried deep beneath the
Earth‟s surface, microorganisms have an uncanny ability to survive under these
conditions. This ability to survive has fascinated scientists for nearly a century, but
the recent development of metagenomics and „omics tools has allowed us to make
huge leaps in understanding the remarkable complexity and versatility of
extremophile communities. Here, in the context of the recently developed
metagenomic tools, we discuss recent research on the community composition,
adaptive strategies and biological functions of extremophiles.