Barcelonas transformation into the worlds leading smart city is explained by one of its chief protagonists. SMART CITY Barcelona provides an essential guide for innovation and leadership for all those who participate in the design of cities in the 21st century. The Barcelona municipality is a driving force in the creation of city employment, well-being and opportunity. What can the world learn from the Barcelona model? What should municipal governments priorities be when committing to this development model? What are smart cities and what are they not? Why do they generate so much controversy? Based on the authors experience as deputy mayor of urbanism, housing, infrastructures, environment, energy, ICT, and innovation in Barcelona City Council, as well as a consultant and lecturer to cities across the world (Singapore, Ho Chi Minh City, Mumbai, Delhi, Pune, Doha, Dubai, Oslo, Prague, Moscow and Bogota, to name a few), SMART CITY Barcelona presents twelve theoretical and practical lessons for all citizens, civil servants, politicians, architects, city planners and businessmen who wish to contribute to the design of 21st century cities. The urban development vision to integrate information and communication technology (ICT) and internet of things (IoT) technology in way that makes best use of the resources and human assets peculiar to a city has attracted popular attention and social media comment as people view this new vision as the promotion of the artistic, spiritual and political life of the city they live in. colour illus