The Earth is estimated to have about a nonillion (1,000,000,000,000,000,000,000,000,000,000) microbes in, on, around, and under it, comprised of an unknown but very large number of distinct species. Despite the widespread availability of microbial genome data — close to 2,000 microbes have been and are being decoded to date — a vast unknown realm awaits scientists intent on exploring microorganisms that inhabit this “undiscovered country.”