Microbes make up most living matter and display tremendous diversity, yet less than 1% have been cultured and studied.

Microbes do most of the biogeochemical cycling that keeps the world habitable.

Microbes first appeared on Earth about 3.8 billion years ago.  They are critically important in sustaining life on our planet.

Microbes are roots of life's family tree.  They will help us understand how more complex genomes developed.

Microbes generate at least half the oxygen we breathe.

Microbial studies will help us define the entire repertoire of organisms in specialized niches and, ultimately, the mechanisms by which they interact in the biosphere.

Microbes offer unusual capabilities reflecting the diversity of their environmental niches.  These may prove to be useful as a source of new genes and organisms of value in addressing bioremediation, global change, biotechnology, and energy production.

Microbial communities are excellent models for understanding biological interactions and evolution.

Microbial genomes are modest in size and relatively easy to study (usually no more than 10 million DNA bases, compared with some 3 billion in the human or mouse genomes).

Diversity patterns of microorganisms can be used for monitoring and predicting environmental change.

Most microbes do not cause disease.