Microbiology is the study of the invisible world of microorganisms, organisms so small that microscopes and other special equipment are needed to directly observe them. They play a crucial role in maintaining the Earth's atmosphere and help decompose organic matter. Microbiology plays a role in a great variety of areas, including optimizing soil for agriculture, developing preservatives and pharmaceuticals, genetic engineering, and developing climate change models. The discovery of microbes was instrumental in controlling infectious disease outbreaks that had, for centuries, wiped out entire populations. This new volume introduces readers to the main principles of microbiology, its importance, and its many real-world applications. Categories include: Major groups of microorganisms; Adaptive immunity; Microorganisms and human disease; Environmental microbiology; Applied and industrial microbiology; and Microbiomes. This volume will be a helpful resource for students and researchers looking for a solid grounding in the key terms and aspects of this field.