The study applies the Multiple Streams Approach, which conceptualizes policy-making as shaped by ambiguity, time constraints and contingency. The approach assumes that there are three independent streams flowing through the political system: the problem stream, the policy stream and the political stream. Agenda change is likely to happen when the three streams are ripe, a window of opportunity opens and when a policy entrepreneur becomes active. The book advances the Multiple Streams Approach by adapting it to the EU context, incorporating the Regulatory Scrutiny Board as a previously overlooked actor and integrating trilogue negotiations into the model by distinguishing three coupling processes in the decision making phase.