"No Trust, No City!" was the longtime credo on their website; "Some Ideas for Better Cities" was their first joint lecture series; and Acting in Public was their first book. For over twenty years, the architecture collective raumlaborberlin has been searching for new spaces of encounter and for ways of achieving cooperative urban development. Together with experts from various disciplines, they experiment with new forms of urban practice, participation, and the joint production of space. Polylemma explores the work of the collective from diverse perspectives. Its nine members visit the sites of their work, come together with long-standing colleagues and critics, dissect the mechanisms behind their actions, and reflect on the tools and methods of their research-based practice. Examining numerous projects, they discuss strategies for learning together, experimental building, radical recycling, and cooperative urban development. The book is a call to action: space becomes an actor that fundamentally questions design itself and the role of architects. It offers an extensive collection of photos and drawings, analyses and ideas, tutorials and building instructions, that continually test and explore the parameters for action in urban space. Polylemma asks: How do we want to live together in the future? It is a request to think space openly; a plea for the city as a sphere of action.