Micro-organisms play a major role in the geochemistry of the planet, forming the basic stage in the food chain, and thus sustaining the existence of higher evolutionary life. The continuing interaction between these living organisms and the environment, combined with their exploitation by man are shaping the material world today.Over the last few years our understanding has increased considerably due to the development of new technology and the emergence of new paradigms which have enabled the microbiologist to view the microbial world, and its significance to life, with new eyes. Combining the basics of science with the most up-to-date new material, and incorporating high quality photographs and graphics, this book is valuable as both a textbook and reference guide for students and professionals.