More than thirty years have passed since János Kornai's book 'Anti-Equilibrium' appeared. This was the first work in international literature to criticize comprehensively the general theory of equilibrium, moreover through the value theory of Debreu and the Arrow-Debreu Model. The sharpest reaction to the criticism came from Frank H. Hahn, and Kornai returned to this in his recent autobiography. This article reconstructs the main points in the Kornai-Hahn debate, including its antecedents in the history of theory, and examines the validity of the criticisms and ripostes. It will be seen that Hahn's objections have not been endorsed in every respect by the latest economic theories.