A special issue of the journal "Critical Review of International Social and Political Philosophy". This study covers the theory, history and future of utopianism (the belief in an ideal society). Utopias are born out of hope and the desire for social change and for better ways of living. Utopian tests are not mere fantasies but have transformative power: they insist that we have the power to change the world and that society and politics can be different. This collection of essays addresses the important function of utopianism in social and political philosophy, and includes debates on what its future role will be in a period dominated by dystopian nightmare scenarios. It also raises specific questions such as whether utopias reflect national identity or actually create it, why utopias have often generated technophobia and why so many utopias, although radical in other ways, have retained patriarchal structures. Green utopias and "intentional communities" and living utopian experiments such as Findhorn and Twin Oaks, are considered as political theory put into practice.