Valid publication of names of prokaryotes according to the rules of nomenclature: past history and current practice.

It is now 30 years since the concept of valid publication was introduced into prokaryote systematics in such a way that a system of registration/indexing was integrated. Despite the success of this system and the introduction of the Approved Lists of Bacterial Names, accompanied by a new starting date in prokaryote nomenclature, there is a need to review both the historical aspects and current practices so that the current generation of prokaryote systematists have an up-to-date overview of some of the key elements.