While we are used to looking around us, we are less used to listening to what happens around us. And yet, the noises we produce reveal our way of life, and learning to master them is a necessity. This book aims at drawing the reader's attention to the sound of the urban environment. The topic is by its very nature complex, as it involves sounds and noises, urban space and social activities. Using an interdisciplinary approach, it examines an incongruous selection of experimentations from the domains of music, art and architecture. Significant case studies of pieces of music, public art works and scientific research in the field of urban planning are analyzed, investigating the methods that have been adopted and the aural processes that have been generated. It then uses the findings to reconstruct the underlying theories and practices and to show what might be drawn from these procedures applied to urban planning. The overall objective is to learn to build and enrich space with sound, arguing that there is a need to reconsider architecture and urban planning beyond the merely physical, and to look to the world of the arts and other disciplines. In doing so, the book guides the reader toward a sensorial architecture, and more generally toward consciously creating environmental architecture which is sustainable and connects with art and which diffuses a culture of sound.