20 years ago, in 1998, Scientific American published a paper by Colin J. Campbell and Jean H. Laherrère titled “The End of Cheap Oil” [1], starting a debate on oil depletion continuing to the present day. It was the return of a viewpoint on oil depletion which had been proposed more than 40 years before by Marion King Hubbert [2]⁠ and, in later years, largely forgotten. In their paper, Campbell and Laherrère updated Hubbert’s model with new reserve estimates and proposed that the world’s crude oil production would peak around 2004–2005, and then start an irreversible decline. Shortly afterward, Colin Campbell proposed the term “peak oil” for the highest global oil production level. The term was to become popular over the following decade, generating a true movement of ideas sometimes called the “peak oil movement.” Today, these predictions turn out to have been only partially correct, mainly because the role of “non-conventional” oil was underestimated. The peak oil movement seems to have faded away, while the concept seems to have disappeared from the debate and to be commonly described has having been “wrong.” The present paper reviews the cycle of the peak oil movement, examining how the peak oil concept was understood with the public and the decision makers and what caused its diffusion and its demise, at least up to the present time.