Groundwater Earth tells the hidden history of the largest distributed mass of freshwater on the planet. The fruits of groundwater are all around us: half the global population drinks it, and over half of all crops are irrigated with it. Most access to groundwater is done by mechanized wells, known as tubewells, which are largely privately owned. First patented in the 1860s, tubewells allowed communities across the world to thrive, but today they threaten to bleed the earth dry. Tubewells dot the Italian peninsula, which adversely affects the delivery of water to Rome and other major cities. My third book, Groundwater Earth, investigates how this came to be and why examining the history of groundwater technologies—from ancient aqueducts to deliver groundwater from the Peschiera Springs in the Apennine Mountains to the proliferation of privately owned tubewells—goads us to think differently about how the subsurface of the Earth might inform how we shape the surface.