Viruses are some of the most feared organisms on the planet, especially in the wake of the COVID-19 pandemic. Many can cause severe illness in humans and animals, although some viruses can actually have a protective effect. Viewing viruses under a microscope helps scientists understand more about them and figure out how to fight the ones that are harmful. Vibrant full-color photographs and illuminating graphic organizers help readers form a better understanding of these microorganisms, giving them insight into the ways we can both use and fight viruses.