This book examines the heretical and millenarian movements that challenged social and ecclesiastical authority in Europe from the 1200s into the 1500s. Although Vaneigem discusses a number of different movements such as the Cathars and Joachimite millenarians, his main emphasis is on the various manifestations of the Movement of the Free Spirit in Northern Europe. He sees not only resistance to the power of state and church, but also the immensely creative invention of new forms of love, sexuality, community and exchange. Vaneigem is particularly interested in the radical opposition presented by these movements to the imperatives of an emerging market-based economy, and he evokes crucial historical parallels with the anti-systemic rebellions of the 1960s. The book includes translations of original texts and source materials.