The high voting threshold in the Council together with conflicting national preferences should frustrate effective European problem-solving. This famous prediction of the "joint-decision trap" (JDT) is at odds with Europe's dynamic environmental policy. Yet there is scarce research on the limited impact of the JDT in this realm. We know little, therefore, about the conditions of effective environmental policy-change in the EU. By comparing cases of stability and change, including CO2-limits for passenger cars and the phase-out of inscandescent lamps, the book examines the ways in and out of the JDT in environmental policy. It shows how both the highly politicized summit level and the bureaucratic "comitology" facilitate change by acting as informal bypasses to the Council. The book contributes to a better understanding of the JDT. It speaks to the recent debate about Europe's "new intergovernmentalism" and the reliance on "informal politics," especially in the wake of the Euro crisis.