Episodes in the transformation of our understanding of sound and space, from binaural listening in the nineteenth century to contemporary sound art. The relationship between sound and space has become central to both creative practices in music and sound art and contemporary scholarship on sound. Entire subfields have emerged in connection to the spatial aspects of sound, from spatial audio and sound installation to acoustic ecology and soundscape studies. But how did our understanding of sound become spatial? In Stereophonica, Gascia Ouzounian examines a series of historical episodes that transformed ideas of sound and space, from the advent of stereo technologies in the nineteenth century to visual representations of sonic environments today.