Viruses are the smallest living things known to science, and yet they hold the entire planet in their sway. We are most familiar with the viruses that give us colds or the flu, but viruses also cause a vast range of other diseases. Viruses have been a part of our lives for so long, in fact, that we are actually part virus: the human genome contains more DNA from viruses than our own genes. Meanwhile, scientists are discovering viruses everywhere they look: in the soil, in the ocean, even in deep caves miles underground. Here, science writer Carl Zimmer presents the latest research on how viruses hold sway over our lives and our biosphere, how viruses helped give rise to the first life forms, how viruses are producing new diseases, how we can harness viruses for our own ends, and how viruses will continue to control our fate for years to come. --From publisher description.