In architecture, cities are points of departure and arrival. They are fact and abstraction, a tangible exterior and the pure product of the mind. To understand them, one must venture along the path that travels between these two separate realities. This book attempts to reproduce this trajectory and to describe it through the traces it has produced. This book’s structure and shape hinge on two different perspectives on urban planning: the city as the site of experience and thought, and the city as the locus of architectural endeavor and change. The white notebooks contain writings, reflections, and observations about the urban experiences we have collected over a ten-year period. They are arranged by the names of the cities that inspired them. These notes were often written during trips to conferences or projects. They do not aspire to certainty, but are instead to be read as a series of questions and hypotheses. The black notebooks, on the other hand, seek to lay out the scope of our research and to describe architecture as we practice it, namely by discussing the major themes that run through our projects. In them, we have tried to develop the idea that projects are not ends in and of themselves, rather tools at the service of a vision. There are no direct connections between these different parts, aside from the ones that readers may of course decide to make.