Book excerpt: Small creatures of great importance. Microbiology, the branch of biology that studies microorganisms and their effects on humans, is a key part of medical training curriculum. Written by a top professor of microbiology and an experienced science writer, this book is a basic microbiology course that can be understood by anyone, including medical students, professionals wanting to bone up on the subject, and laypersons wanting to know about the topic. • Includes coverage on microbes and their relationship with each other, the body’s immune system, infectious diseases, biotechnology, and bioterrorism