This book is an introduction to the wide-ranging topic of NGOs and development combining a critical overview of the main research literature with a set of up-to-date theoretical and practical insights drawn from experience in Asia, Europe, Africa and elsewhere. The second edition highlights the importance of NGOs in development, and fully engages with the criticisms that the increased profile of NGOs in development now attracts. It considers new issues, such as the rise of social media and management concerns around staff safeguarding, and covers themes like market-based development and social enterprise in more detail. The diversity of NGOs and their roles is discussed within the background of broader histories of struggle as well as within the ideological context of neo-liberalism. Using a broad range of short case studies of successful and unsuccessful interventions, the authors analyze how interest in NGOs has both reflected and informed wider theoretical trends and debates within development studies. The book argues that NGOs are central to development theory and practice and are likely to remain important actors in development in the years to come. This critical overview will be useful to students of development studies at undergraduate and masters levels in fields and disciplines as diverse as International Development Studies, International Relations, Geography, Anthropology, Global Studies and Politics, International Studies, as well as general readers and practitioners.