The rapid development of molecular methods over the last few years has allowed considerable progress to be made in understanding the occurrence and roles of microorganisms in the natural environment. This Special Issue of FEMS Microbiology Reviews brings together data from a number of laboratories to give an overview of the current state of knowledge. The Editorial Board thanks Dr. Bernhard Schink for editing this volume and the authors for producing such readable and erudite reviews in a timely manner.

Nigel L. Brown

Chief Editor