Think tanks are non-state actors that have mobilised expertise to contribute to policy thinking. These organisations are independent policy research institutes but are not simply learned societies. Instead, many act as policy entrepreneurs within both domestic and international policy domains proffering policy advice on crossnational problems of pollution, pandemics, trade and so forth. Furthermore, some institutes contribute to processes of global and regional governance. They supply information and expertise, and encourage consultation and exchange between official and other private actors. Through their scholars, research reports and intellectual advocacy, think tanks provide input to international conferences, the monitoring of international agreements and project development in organisations such as the World Bank. Some provide a venue for ‘closed discussions’ or a prestigious non-governmental forum for international conferences and visiting dignitaries. Accordingly, the think tank phenomenon warrants greater attention not only because there has been a massive proliferation of these organisations across the globe but because they appear to represent an important component of burgeoning transnational policy elites.