Mohammad Saghir Khan, Ph.D., is an Associate Professor at the Department of Agricultural Microbiology, Aligarh Muslim University, Aligarh, India. Dr. Khan received his M.Sc. from Aligarh Muslim University, Aligarh, India, and his Ph.D. (Microbiology) from Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, India. He has been teaching Microbiology to post-graduate students for the last 13 years and has research experience of 17 years. In addition to his teaching, Dr. Khan is engaged in guiding students for their doctoral degree in Microbiology. He has published over 50 scientific papers including original research articles, review articles and book chapters in various national and international publication media. Dr. Khan has also edited three books published by the leading publishers. His interest in the various aspects and applications of Microbiology coupled with his classroom and laboratory experience makes him uniquely qualified to author this book. He is deeply involved in research activities focusing mainly on rhizobiology, microbiology, environmental microbiology, especially heavy metals-microbes-legume interaction, bioremediation, pesticide-PGPR-plant interaction, biofertilizers and rhizo-immunology. Almas Zaidi, received her M.Sc. and Ph.D. (Agricultural Microbiology) from Aligarh Muslim University, Aligarh, India and is currently serving as Guest faculty/Assistant Professor at the Department of Agricultural Microbiology, Aligarh Muslim University, Aligarh, India. She has been teaching Microbiology at post graduate level for the last five years and has research experience of 13 years. She has published about 40 research papers and review articles in journals of national and international repute. She has also contributed chapters to different books. Dr. Zaidi has edited three books published by the leading publishers. Her main focus of research is to address problems related with rhizo-microbiology, microbiology, environmental microbiology, and biofertilizer technology. Javed Musarrat, M.Sc., Ph.D. (Biochemistry), former Chairman of the Department of Agricultural Microbiology and Ex-Dean, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India, is presently working as a Professor, DNA Research Chair at the King Saud University, Riyadh, Saudi Arabia. He has been teaching Biochemistry, Microbiology and Molecular Biology to post-graduate students for the last 23 years and has research experience of about 25 years. He has contributed more than 50 national and international scientific publications. Dr. Musarrat has edited two books published by the leading publishers. He is associated with several scientific bodies such as Department of Biotechnology, Council of Scientific and Industrial Research, University Grants Commission, Indian Council of Agricultural Research, UPCST, and CCRUM in various capacities. His major area of interest includes the molecular microbiology, microbial ecology and genetic toxicology.