Book excerpt: This book offers the first comprehensive, in-depth treatment of microbial diversity for undergraduate and graduate students. Using a global approach, Microbial Diversity illustrates the impact of microorganisms on ecological and Earth system phenomena. Accompanied by a devoted website with resources for both instructors and students: www.blackwellpublishing.com/ogunseitan Uses key ecological and global phenomena to show the continuity of microbial contribution. Illustrates the importance of microbial diversity for the understanding of global physiochemical and biological processes. Presents analyses of microscopic, culture, molecular, and phylogenetic systematic methods. Shows the relevance of microbial diversity to global environmental problems, such as climate change and ozone depletion. Features numerous illustrations, including over 60 4-color photographs of microbes.