Did you know that the tools that have become absolutely integral to your life - your laptop, iPod, and cell phone - are all powered by lithium batteries? Chances are you've got some lithium on your person right now. The third element on the periodic table may also hold the key to an environmentally sustainable, oil-independent future. From electric cars to a "smart" power grid that can actually store electricity, lithium - a metal found only in some of the most uninhabitable places on Earth - is setting us on a path toward a carbon-free future and shifting the geopolitical chessboard in profound ways. The science reporter Seth Fletcher takes us on a fascinating journey, from the salt flats of Bolivia to the labs of MIT and Stanford, from the turmoil at GM to cutting-edge lithium-ion battery start-ups, introducing us to the key players and ideas in an industry with the power to reshape the world.