Living in a Microbial World is a textbook written for students taking a general microbiology or microbiology-themed course for non-science majors. It teaches the essential concepts of microbiology through practical examples and a conversational writing style intended to make the material accessible to a wide audience. Each chapter contains a series of cases intended to motivate learning the microbiology concepts. The cases present microbiology in the news, in history, in literature, and in scenarios of everyday life. The reader will learn the role that microorganisms play not only in our health but also in ecosystem processes, our diet, industrial production, and human history.