?Wherever you go, tiny hitchhikers tag along for the ride,? this intriguing illustrated nonfiction book begins. ?The hitchhikers are actually microbes --- tiny living things so small that you need a microscope to see them. And every person carries around trillions and trillions of these critters.? Six of the most common ?critters? that live in and on our bodies are introduced here: bacteria, archaea, viruses, fungi, protists and mites. Each one has its own preferred environment, and readers will be startled (and likely a little grossed out!) by the many places they live, including the hair follicles on our faces, the folds of our tongues and the lengths of our guts. Just as surprising, only some of them are ?bad guys? that cause disease, and many of them are actually ?good guys? that keep us healthy. There's even research currently being done on ways to improve or fix our collection of microbes as a way to make us healthier.