Currently, the various departments of justice of Barcelona and L'Hospitalet de Llobregat are scattered in 17 buildings distributed between the two cities, with functional frustrations for both users and employees. A new conjoined City of Justice will improve efficiency and allow working spaces to adapt and absorb the constant transformation of the judicial body while allowing extra space for future growth. This mograph is devoted to the winning project by b720 architects and David Chipperfield Architects, describing all details from the design process to the construction phase. The most significant proposition breaks up the massive program requirements (241.519,92 m2) into a series of separate but inter-related buildings on a public plaza, engendering a spatial composition that attempts to break the rigid and molithic image of justice. This proposal also attempts to provide an equilibrium in the relationships between the different working areas, public areas and landscape. The book is organized in four different sections. The first chapter is an interview between David Chipperfield and Fermin Vazquez; the second gives an overview of the project with visual material and drawings; part 3 talks about the execution of the building by B720, and there is a final technical analysis on the pigmented concrete by Lanxess, the chemical company that collaborated on the project. B720 is a studio founded in 1997 and managed by Fermin Vazquez. It has offices in Madrid, Barcelona and Porto Alegre (Brazil).