As a transdisciplinary puzzle, between international relations and public policy, foreign policy analysis (FPA) owes much to the study of decision-making processes and its early pioneers (Richard Snyder, James Rosenau, Harold and Margaret Sprout . . . ). Formulated and implemented by state agents, foreign policy fully belongs to the field of public policy studies, whose approaches have proved relevant to analyze its formulation. Still, it remains singular for several reasons. In constant interdependence with extraterritorial and mostly unpredictable actors or events, it is more reactive (or at least less proactive) than most domestic policies. Vulnerable to various transnational linkages, foreign policy also leads the analyst to rethink several pillars of public policy studies, such as the role of public opinion, the nature of elites, or the feasibility of evaluation. Its implementation, in particular, depends on the leeway resulting from foreign processes initiated in remote states or societies. Because what is at stake is national identity, reputation, or status, the national interest, and war and peace, the possibility of nonrational, psychologically biased, or even passionate responses to a political problem is higher. The emergence of nonstate actors (nongovernmental organizations, companies, religious groups), substate entities (regions, federated states), and suprastate organizations in international politics is a compelling factor that urges us to rethink foreign policy as public policy. The fading boundaries between domestic and international dimensions, as well as between public and private strategies, have a deep impact on the analysis. The theorization and practice of new kinds of policy networks are likely to be at the heart of future research agendas, both in international relations and public policy studies.