Taking Action brings into focus the sustainable design of urban transformation and the preparation of densely structured urban spaces for future challenges. How can climate change and spatial inequalities be tackled under crisis conditions and in view of limited spatial and other resources? How can we relate our ambitious and broadly defined goals to the reality of local conditions and everyday spaces? How can knowledge be translated into action? While basic spatial relations are currently being renegotiated in cities throughout Europe, it is in Athens that some of the most pressing urban problems have been crystallized in order to establish unique spaces of experimentation. Approaching these multi-dimensional questions from different perspectives, the authors seek to identify possible sites of intervention, suggest new models of transformation, and activate the potentials of urban landscapes for positive urban change.