Chapter 9 combines insights from the datasets presented in Chapter 4 with the case studies in Chapters 5 to 8. A key insight is that present-day budgeting and resource decision-making, with segmented budgets and informal proceduralization, cannot be understood without considering complex interests of states and of other donors, and without paying attention to decentralized or otherwise fragmented IO bureaucracies. Methodologically, the chapter reflects on how insights from a comparative approach to UN and IO budgeting need to be combined within a systemic research perspective that looks at the UN system as a whole. Thus, the complex P–A model developed in this book both answers and raises questions for a better understanding of budgeting dynamics within IOs. In the final section, the chapter returns to foundational disciplines to discuss how the findings of the book contribute to the disciplines of political economy, public policy, international relations, and public administration.