Why have some countries gone further than others in adopting market–conforming policies? Although previous studies have highlighted political parties, production regimes, and political institutions, this book points to the varying position of economic experts within the state to explain the persistent differences in economic policies across developed countries. Although economists were key agents of the turn toward the market in public policy, their impact depended crucially on the historical institutionalization of economic expertise within state bureaucracies. Drawing on insights from the sociology of professions and public administration, the book puts forward a novel argument about economists as policy actors. This argument emphasizes on the one hand the historical–institutional preconditions for the influence of economists and on the other hand the analytical and normative resources available to economists in policy making. The argument is explored through a comparative investigation of taxation policy, one of the core areas of market-oriented reform from 1980 onwards. Based on historical evidence and a large number of in–depth interviews with policy–making elites, the book analyzes the actors and institutions that shaped tax policy across a set of small, advanced countries–New Zealand, Ireland, Norway, and Denmark–over the period 1980–2010. This analysis yields surprising conclusions about the driving forces behind market-oriented reform.