["The Economic History Review, Volume 79, Issue 2, Page 634-660, May 2026. ", "\nAbstract\nThis paper examines the distributive effects of personal income taxation in Sweden, the United Kingdom, and the United States during the first half of the twentieth century. We estimate the evolution of marginal and average effective tax rates across the income distribution and calculate the corresponding indices of progressivity and redistribution. Our results show that redistribution through income taxation increased during the period with varying intensity and mechanisms. During the First World War, this was a joint effect of increases in the amount of revenue collected and progressivity. In contrast, during the Second World War, revenue increased again, but progressivity diminished.\n"]