Recently think tanks have encountered significant challenges in carrying out their research and networking functions due in part to the expansion of populism in political, social and economic governance institutions around the globe. As a result of these and other pressures, including funding shortfalls at the organizational and project level, many have sought to secure more prominent roles in the marketplace of ideas. Their higher visibility has generated increased scrutiny from scholars, who have tried to come to terms with what think tanks are, the functions they perform and the strategies they employ to shape public opinion and public policy. While these explorations have raised the profile of think tanks in the scholarly literature, this volume seeks to fill many of the remaining gaps in the development of evaluation methodologies as they relate to their operations, ontologies and durability. The introduction outlines how the volume’s contributors examine the evolution of think tanks and their influence on policy discourse and the body politic.