Oil and gas have provided much of the energy to drive the Industrial Revolution over the past two centuries, but they are finite resources formed in the geological past, which means they are subject to depletion. The peak of world oil discovery in the 1960s must deliver a corresponding peak of production. The onset of the decline of this critical energy source will likely have far-reaching social, economic, and political consequences. This turning point in history would be self-evident but for lax reporting standards and ambiguous definitions. © 2012 John Wiley & Sons, Ltd.