William Rankin is an Assistant Professor of the History of Science at Yale, where he specializes in the history of cartography. In the last decade, beyond his work as an historian, he has also emerged as a celebrated mapmaker in his own right. He's been posting his maps at radicalcartography.net, which has now logged over six million unique visitors. His work has been written about in the New York Times, Le Monde, the Washington Post, The Economist, The Atlantic, Slate, Vox, and collected in several editions of Best American Infographics.