This book provides the first historical and comparative study of the 'transnational activist'. A range of important recent scholarship has considered the rise of global social movements, the presence of transnational networks, and the transfer or diffusion of political techniques. Much of this writing has registered the pivotal role of 'transnational' or 'global' activists. However, if the significance of the 'transnational activist' is now routinely acknowledged, then the history of this actor is still something of a mystery. Most commentators have associated the figure with contemporary history. Hence much of the debate around 'transnational activism' is ahistorical, and claims for novelty are not often based on developed historical comparison.