Signal is an ongoing book series dedicated to documenting and sharing compelling graphics, art projects, and cultural movements of international resistance and liberation struggles. Artists and cultural workers have been at the center of upheavals and revolts the world over, from the painters and poets in the Paris Commune to the poster makers and street theatre performers of the recent counter globalization movement. Signal will bring these artists and their work to a new audience, digging deep through our common history to unearth their images and stories. We have no doubt that Signal will come to serve as a unique and irreplaceable resource for activist artists and academic researchers, as well as an active forum for critique of the role of art in revolution.