Tough choices loom if the world wants to go green. The United States and other countries must decide where and how to procure the materials that make our renewable energy economy possible. To build electric vehicles, solar panels, cell phones, and millions of other devices means the world must dig more mines to extract lithium, copper, cobalt, rare earths, and nickel. But mines are deeply unpopular, even as they have a role to play in fighting climate change. These tensions have sparked a worldwide reckoning over the sourcing of these critical minerals, and no one understands the complexities of these issues better than Ernest Scheyder, whose exclusive access has allowed him to report from the front lines on the key players in this global battle to power our future.