Asphalt: A History

La Brea Tar Pits once trapped prehistoric mammals. Today that killer has a chemical cousin in the Athabasca oil sands of Alberta, Canada—immense deposits of natural asphalt destined for upgrading to synthetic crude oil. If the harvesting of this natural asphalt continues unabated, we might find ourselves stuck in a muck of a different kind. Humanity has used asphalt for thousands of years. This humble hydrocarbon may have glued the first arrowhead to the first shaft, but the changes wrought...