The subtitle tells the story. In the early 2000s, many pundits and politicians talked up “peak oil”, “energy scarcity,” and all that. In a geological heartbeat later—about a decade—the world had entered an era of “energy abundance,” largely due to innovations that allowed producers to crack into shale formations to release massive new sources of oil and gas. The United States has gone furthest and fastest in fracking and is setting records for oil and gas production. For the US, says O’Sullivan, this has been an economic, strategic, and environmental game-changer. For the rest of the world, the effects are more differentiated but hardly less profound.