In the time of COVID-19, it seems everyone is talking about viruses. But what is a virus, and how does a virus spread? Readers find the answers as they explore this comprehensive introduction to a basic biology curriculum concept. The fact-filled main text is paired with graphic organizers and full-color photographs, and detailed sidebars provide additional information about various viruses and the diseases they cause. In addition, readers are presented with a series of questions after each chapter to help them think critically about this topic and how it affects their lives today.