This publication inquires into the future of post-industrial cities framing and speculating on different industrial contexts: archipelagos (Eibar), fabrics (Cobo Calleja), assemblies (Detroit). Currently 55% of the world's population lives in cities, predictably reaching 70% in 2050. Cities are organisms in continuous transformation: growth, change, but also shrinking or collapse. Open City explores and speculates from contemporaneity about the future of the post-industrial city, where industrial archipelagoes (S), frames (XL) and obsolete or deprogrammed singularities (M/L) represent critical contexts but also opportunities for a new Open City. Open Systems have been the research focus of CoLab since 2013. This book collects some relevant and engagingly contemporary insights. It also includes new unpublished interviews and articles with international participants leading players in this field. CoLaboratorio is a research, prototyping and production space. From the contemporary architecture project CoLab works around industrialization, flexible systems, project participation and collaborative dynamics.