This article analyzes Keynes's Economic Possibilities for our Grandchildren an essay presenting Keynes's views about economic growth into the 21st century from the perspective of modern growth theory. I find that the implicit theoretical framework used by Keynes to form his expectations about the 21st century world economy is remarkably close to modern growth models, featuring a stable steady-state growth path driven by technological progress. On the other hand, Keynes's forecast of employment in the 21st century is far off the mark, reflecting a mistaken view that the income elasticity of leisure is much higher than that of consumption