This book provides a comprehensive analysis of Lithuanian foreign policy by employing the theory of small states and the agent-perspective to assess how President Dalia Grybauskaitė impacted Lithuanian foreign policy in 2009–2019 and which, in turn, could affect changes in international structures. The book is based on original interviews with Grybauskaitė and all her foreign policy advisors, as well as other Lithuanian diplomats and Ministers of Foreign Affairs. In addition to providing an important case study of Lithuanian foreign policy, this monograph also discusses the impact an agent formulating and executing small-state foreign policy may have on the ‘grand structures’ of international relations, such as the EU and NATO. For its investigation of the mutual relationship between agent and structure, this monograph draws on the literature on foreign policy analysis (FPA) and asks questions about the extent to which a particular leader of foreign policy may determine a specific policy decision or outcome. This book will be of particular interest to students of the Baltic region and Russia-Baltic relations, as well as to political scientists and researchers interested in FPA literature, and small-state security.