Throughout the 20th century socialism and war have been intimately connected, the two world wars providing the opportunity and the impetus for a variety of socialist experiments. This volume in a series of works by Hayek, documents the evolution of his thought on socialism and war during the 1930s and 1940s. Opening with Hayak's arguments against market socialism, the book continues with his writings on the economics of war, many in response to the proposals made in John Maynard Keynes's pamphlet "How to Pay for the War". The final section presents articles which anticipated "The Road to Serfdom", Hayak's meditation on the dangers of collectivism. An appendix contains a number of book reviews written by Hayak during this crucial period, and an introduction which sets the work in context.