Methane and its oxidation product, methanol, have occupied an important position in the chemical industry for many years: the former as a feedstock, the latter as a primary chemical from which many products are produced. More recently, the role played by methane as a potent "greenhouse" gas has aroused considerable attention from environmentalists and clima tologists alike. This role for C compounds has, of course, been quite 1 incidental to the myriad of microorganisms on this planet that have adapted their life-styles to take advantage of these readily available am bient sources. Methane, a renewable energy source that will always be with us, is actually a difficult molecule to activate; so any microorganism that can effect this may point the way to catalytic chemists looking for con trollable methane oxidation. Methanol, formed as a breakdown product of plant material, is also ubiquitous and has also encouraged the growth of prokaryotes and eukaryotes alike. In an attempt to give a balanced view of how microorganisms have been able to exploit these simple carbon sources, we have asked a number ofleading scientists (modesty forbids our own inclusion here) to contribute chapters on their specialist areas of the subject."

Methane and its oxidation product, methanol, have occupied an important position in the chemical industry for many years: the former as a feedstock, the latter as a primary chemical from which many products are produced. More recently, the role played by methane as a potent "greenhouse" gas has aroused considerable attention from environmentalists and clima tologists alike. This role for C compounds has, of course, been quite 1 incidental to the myriad of microorganisms on this planet that have adapted their life-styles to take advantage of these readily available am bient sources. Methane, a renewable energy source that will always be with us, is actually a difficult molecule to activate; so any microorganism that can effect this may point the way to catalytic chemists looking for con trollable methane oxidation. Methanol, formed as a breakdown product of plant material, is also ubiquitous and has also encouraged the growth of prokaryotes and eukaryotes alike. In an attempt to give a balanced view of how microorganisms have been able to exploit these simple carbon sources, we have asked a number ofleading scientists (modesty forbids our own inclusion here) to contribute chapters on their specialist areas of the subject.

The chapters making up this volume are based on the presentations given by their authors at the NATO Advanced Research Workshop (ARW) , also entitled "The Microbiology of Atmospheric Trace Gases: Sources, Sinks and Global Change Processes", held between 13-18 May 1995 at II Ciocco, Castelvecchio Pascoli, Tuscany, Italy. Four reports of Working Group discussions on aspects of trace gas microbiology and climate change are also included in the volume, prepared by rapporteurs designated at the ARW. All the papers here presented have been subjected to peer review by at least two referees and corrections and amendments made where necessary before their acceptance for pUblication in this volume. The ARW was set up to address a wide range of issues relating to atmospheric trace gas microbiology and the organizing group was aware of the burgeoning of studies on gas metabolism and on global effects of atmospheric trace gases over the past two decades. This research effort has led to a number of specialist and generalist meetings including the triennial series of symposia on the metabolism of one-carbon compounds, colloquia concerned with dimethyl sulfide and its precursor, DMSP, through to the Intergovernmental Panels on Climate Change, which have addressed the impact of increasing levels of atmospheric carbon dioxide, methane, nitrous oxide and chlorofluorocarbons on global climate. Over recent years methane and nitrous oxide showed rates of increase in the atmosphere of 40-48 and 3-4. 5 Tg/year, respectively.