This first issue in the ‘Complex Buildings’ series contains projects and articles by a diverse group of international designers and architects, among them, Urban Think Tank, Studio Muoto, Bruther, NL Architects, Bel, Flores Prats, Maio, V+, De Smet Vermeulen, and JaJa. To help define and investigate the complex condition of the hybrid project, which is often a mixed-use building or architectural solution that seeks to revitalise the urban context while improving spatial efficiency, the featured works are accompanied by historical references.