This book looks at the future of advertising from the perspective of pervasive computing. Pervasive computing encompasses the integration of computers into everyday devices, like the covering of surfaces with interactive displays and networked mobile phones. Advertising is the communication of sponsored messages to inform, convince, and persuade to buy. We believe that our future cities will be digital, giving us instant access to any information we need everywhere, like at bus stops, on the sidewalk, inside the subway and in shopping malls. We will be able to play with and change the appearance of our cities effortlessly, like making flowers grow along a building wall or changing the colour of the street we are in. Like the internet as we know it, this digitalization will be paid for by adverts, which unobtrusively provide us suggestions for nearby restaurants or cafes. If any content annoys us, we will be able to effortlessly say so and change it with simple gestures, and content providers and advertisers will know what we like and be able to act accordingly. This book presents the technological foundations to make this vision a reality.