Chapter 5 details the transformation from the cultural socialism of Tinbergen’s youth to the more political socialism of the Plan Movement. Crucial throughout this transformation was the work of the Belgian Hendrik de Man, who was both the most important intellectual for the cultural socialist youth movement (AJC) and the leader of the Plan Movement in Europe. De Man’s early work was critical of Marxist theory and sought to reconcile bourgeois cultural ideals with an idealistic interpretation of socialism. But during the Great Depression, and especially after the early successes of fascism in various European countries, De Man and other social democrats strongly felt that an immediate response to the economic crisis and the political challenge of fascism was required. Although Tinbergen never became as politically involved as de Man, he was one of the main architects of the Dutch Plan of Labor. This Plan proposed a number of crisis measures, such as public works, but also sought to secure a permanent place for economic expertise within the Dutch state. The chapter concludes with an analysis of the anti-parliamentarian and anti-democratic elements in the Plan movement.