Iron is essential for almost all living organisms as it is involved in a wide variety of important metabolic processes. However, iron is not readily available and microorganisms therefore employ various iron uptake systems to secure sufficient supplies from their surroundings. There is considerable variation in the range of iron transporters and iron sources utilized by different microbial species. Pathogens, in particular, require efficient iron acquisition mechanisms to enable them to compete successfully for iron in the highly iron-restricted environment of the host's tissues and body fluids. In this book, an international team of authors presents a comprehensive collection of reviews on iron uptake and metabolism in various microorganisms, including Rhizobia, Bordetella, Shigella, E. coli, Erwinia, Vibrio, Aeromonas, Francisella, Bacteroides, Campylobacter, Cyanobacteria, Bacillus, Staphylococci, and yeasts. An entire chapter is dedicated to siderophores and another to heme uptake.