A review. Genomic investigations into the diversity of environmental microbes are leading to insights into ecol. dynamics, the evolution of new forms of biol. systems and the discovery of new functions that might be exploited for biotechnol. and biomedical purposes. It is now clear that an understanding of the community structure, function and evolution of bacteria in their natural environments is required to meet the promise of microbial biotechnol. To meet these new challenges, microbiologists are applying the tools of genomics and related high-throughput technologies to both cultured microbes and environmental samples. This work will lead to new views on ecosystems and biol. function together with the biotechnol. enabled by this science