Within the democratisation literature, opposition unity is widely seen as an important requisite to successfully pressure authoritarian rulers into liberalising reforms and in bringing about democratic change. Taking up on this theme, this book examines the myriad ways in which opposition groups across the Arab world have sought to coalesce into broader reform coalitions at the local, national and transnational levels to challenge authoritarian incumbents and their policies. Drawing on original case studies from the region, it sheds light on the diverse nature and objectives of these reform coalitions, and explores the challenges opposition groups face in Arab states in uniting behind a common reform agenda and in driving this agenda forward. Be they electoral pacts, local government coalitions, broader opposition alliances or networks of resistance, this book demonstrates that, although widespread, the record of collective opposition activism in the Arab world is mixed, with many reform coalitions lacking the necessary cohesion and mass appeal to effectively mobilise for change. This book was originally published as a special issue of British Journal of Middle Eastern Studies