This book offers an innovative perspective on the political science debate concerning implementation issues. It focuses explicitly on the theoretical and empirical aspects of previously unrecognized problem-solving potential of actors' knowledge relevant to decision-making on the implementation level. Central to this is the question of whether the model of political control instruments can structure the way and manner in which the implementing actors contribute their knowledge to the political process and thus contribute to a more effective achievement of policy objectives. The book offers a theoretical discussion of this issue, an approach to the analysis of empirical case studies and two case studies from the field of "New Environmental Policy Instruments" in the European Union. Within the framework of the European Emissions Trading Scheme and the Strategic Environmental Assessment, two instruments which offer the addressee prestructured room for manoeuvre are examined.