Microbiology is the study of very small things, both living and nonliving. If you're fascinated by looking at tiny organisms through a microscope, you should take a class in microbiology.
If your job involves microbiology, you're probably a microbiologist, a scientist who studies microorganisms and other microscopic things. Notice the prefix micro- in all of those words? It means "extremely small," from the Greek root mikros, "small or slight." Add this to biology, "the science of living things," and you get microbiology. This branch of science involves looking closely at fungi, viruses, parasites, bacteria, and other microbes.