The roaring (20-) 20s are a decade of anniversaries and milestones. 2020 was the 100th anniversary of Ludwig von Mises's seminal article "Economic Calculation in the Socialist Commonwealth" and the 75th anniversary of F.A. Hayek's seminal article "The Use of Knowledge in Society." 2022 brought a series of significant anniversaries: the 100th anniversary of Mises's Socialism: An Economic and Sociological Analysis as well as the 60th anniversary of James M. Buchanan and Gordon Tullock's The Calculus of Consent: Logical Foundations of Constitutional Democracy, Milton Friedman's Capitalism and Freedom, and Murray Rothbard's Man, Economy, and State. It was also the 20th anniversary of Vernon Smith's Nobel Prize. The works and milestones celebrating anniversaries in 2022 owe much to Mises's and Hayek's pathbreaking contributions. This paper summarizes and contextualizes Mises's and Hayek's arguments about socialism and knowledge and introduces a Southern Economic Journal symposium on the anniversaries of "Economic Calculation in the Socialist Commonwealth" and "The Use of Knowledge in Society."