The Hidden Half of Nature: The Microbial Roots of Life and Health, by David R. Montgomery and Anne Bikle

It took a long time for humans to realize that the plants and animals they saw around them were a small fraction of all the life on earth. When Adam said he had finished naming the animals, God must have laughed. In the seventeenth century, van Leeuwenhoek saw tiny creatures in a drop of water, but he thought them nothing more than an amusing curiosity. In the nineteenth century, scientists realized that van Leeuwenhoek’s creatures caused terrible diseases, so they set out to circumvent or destroy them. It was a futile task: two of the three domains of life—Bacteria and Archaea—are composed entirely of microscopic organisms, and the third domain, Eukarya, which includes animals, plants, and fungi, also contains microbes. Moreover, while some microbes do cause disease, it turns out that most are indispensable for all forms of life. They have created soil on this planet, they make it possible for plants to digest essential nutrients, and they enable essential functions of our own bodies. 

David Montgomery, a geomorphologist, and his wife, Anne Bikle, a biologist and environmental planner, began to study the work of microbes when they moved to Seattle and tried to plant a garden in a yard that was mainly glacial rubble. When Anne came down with cancer, they widened their focus to include microbes in the human body. Their surprising conclusion is that our intestines closely resemble the roots of a plant: both systems depend on interactions with various groups of bacteria in different locations without which we and all vegetation would die. 

They explain all this and much more in a clear and easily understandable narrative written for people who only dimly remember any science they studied in school. The book is continuously interesting, and may actually affect your life. It has a lot to say about how we should manage our gardens and what we should eat to keep our bacteria happy. The Bellingham Public Library has a copy, and copies are available through Amazon and elsewhere on the internet.