Microbiology is a broad term which includes virology, mycology, parasitology, bacteriology, immunology, and other branches. A microbiologist is a specialist in microbiology and these related topics. Microbiological procedures usually must be aseptic and use a variety of tools such as light microscopes with a combination of stains and dyes. As microbes are absolutely required for most facets of human life (including the air we breathe and the food we eat) and are potential causes of many human diseases, microbiology is paramount for human society.
Thumbnail: A cluster of Escherichia coli bacteria magnified 10,000 times. Image used with permission (Public Domain; Eric Erbe, digital colorization by Christopher Pooley, both of USDA, ARS, EMU).