Architects are used to designing visually. In order to expand their basic design tools, this book explores the interactions between sound, space, hearing, and architecture. To this end, the author uses contemporary and historic buildings and projects, but also fictional, philosophical, and theoretical approaches – the idea is not only to define sound as a source, but also as an instrument of architectural space. By introducing a metatheory of "critical hearing", designers are able to acoustically test their projects and contribute to their design with auditive input, already at the design stage.