Transparency is increasingly seen as part of the solution to a complex array of economic, political, and ethical problems in an interconnected world. It is often assumed to result in more accountable and effective governance. The 'transparency turn' in global environmental governance in particular is evident in a wide range of international agreements, voluntary disclosure initiatives, and public-private partnerships. This is the first book to scrutinise this transparency turn critically, and to investigate whether it is a broadly transformative force or plays a more limited, instrumental role.