Abstract
The conviction, due to previous failures, that bacteriology and darwinism were incompatible, has postponed the application of molecular phylogenesis to bacteria. But once introduced, this new field has led to a profound revolution of this science. A stable classification of the bacteria is at last possible; a new domain, the Archae, as distant from the Bacteria as from the Eukarya, has been discovered; noncultivable new species can be identified from the environment. It may even be possible to unravel the pathway of early evolution after the common ancestor. However, controversies on this subject are already disregarded by the new paradigm.