The discovery of oil peaked in the 1960s, meaning that the corresponding peak of production is now imminent. The technical evidence is compelling, but the issue is clouded by denial and obfuscation. Peak oil threatens to be a historic discontinuity as the economic growth of the past Century, which was driven by an abundant supply of cheap oil-based energy, gives way to decline. The population of the world, which grew six-fold in parallel with oil, faces decline, probably accompanied by rising migration pressures. Radical new political structures may be needed in a world facing ever deeper resource and environmental constraints.