This book integrates microbiology and chemistry and looks at the effects of metals on microorganisms and, in turn, the effects of microorganisms on metals and their compounds. The accelerating impact of molecular biology will be felt, particularly in the elucidation of the structure of proteins that bind, transport or have their function modulated by metals. The book begins with coverage of those aspects of coordination chemistry central to an understanding of biological function and discuss the difficulties of analyzing metals in biological systems. An account of the nutritional requirements of microorganisms for growth also highlights experimental difficulties, in this case the provision of adequately chelated metals and speciation and metal limitation. There follows detailed accounts of these essentail elements taken up by cells and the functions of metals, main group and transition, in a wide range of cellular activities.