Microbiology is the science of living things too small to see with just your eyes. Bacteria are the ones people name first, but the field also looks at viruses and other tiny life — including the living things that make bread rise or milk turn into yogurt. You hear the word in science class, in hospitals, and in news about illness. It feels like a lab word, and it is. Though actually, a lot of ordinary life sits on it: washing your hands, cooking meat well, keeping food cold. The people who do this work try to learn how these tiny lives can make us sick, and how some of them help us. It is not the name of the tool you look through; it is the name of the study.