Some 40 million miles of roadways encircle the earth, but we tend to regard them only as infrastructure for human convenience. In Crossings, Ben Goldfarb delves into the new science of road ecology to explore how roads have transformed our world. A million animals are killed by cars each day in the US alone, and roads fragment wildlife populations into inbred clusters, disrupt migration for creatures from antelope to salmon, allow invasive plants to spread, and even bend the arc of evolution itself. But road ecologists are also seeking innovative solutions: Goldfarb meets with conservationists building bridges for mountain lions and tunnels for toads, engineers deconstructing logging roads, and citizens working to undo the havoc highways have wreaked upon cities. A sweeping, spirited, and timely investigation into how humans have altered the natural world, Crossings also shows us how to create a better future for all living beings.