Microbiology is a necessary foundational science for understanding infectious diseases and for better understanding the function of microbes in maintaining health. This textbook focuses on the helping the clinician- and researcher-in-training develop the understanding of microbiology most needed to answer the question:: What information do I need to know that will help me understand how to treat an infected patient. As curricular changes evolve, so does this text. In the current edition, they introduced an e-only systems-based chapter. In the new edition, this is providing the framework for a new section (in print and e) and the foundational chapters will be further reduced. Our best-selling microbiology reference, Medical Microbiology, often known as the “Murray,” is a classic textbook. Nineth edition print unit forecasts are roughly equivalent to 8th edition unit sales. While some medical programs consider the text “too much” for the short time during their course and prefer a smaller text, many educators and students gravitate toward this more comprehensive text and reference. Even residents use it to explore deeper concepts and prepare for boards.