Antonio Violante, FASA, FSSSA, is Professor of Soil Chemistry in the Department of Soil, Plant and Environmental Sciences, University of Naples Federico II, Italy. Dr. Violante has authored or coauthored more than 150 refereed research articles, book chapters, and invited reviews, and has coedited six books. Pan Ming Huang, PhD, FAAAS, FASA, FCSSS, FSSSA, FWIF, is Professor Emeritus of Soil Science at the University of Saskatchewan in Saskatoon, Canada. Dr. Huang has authored over 300 refereed articles and book chapters, written two books, edited seventeen others, and served on many editorial boards. He received the Distinguished Researcher Award from the University of Saskatchewan and the Soil Science Research Award from the Soil Science Society of America. Geoffrey Michael Gadd, PhD, DSc, FIBiol, FLS, FRSE, is the Head of the Division of Molecular and Environmental Microbiology at the University of Dundee, Scotland. Professor Gadd has published over 190 refereed papers, over twenty edited books, and over forty book chapters. He has received the Berkeley Award and the Benefactor's Medal of the British Mycological Society, the Charles Thom Award of the Society for Industrial Microbiology, and is a Fellow of the American Academy of Microbiology.