Around 1900 extensive attempts were made to reform theater architecture, turning away from historical and naturalistic models in search of new esthetic solutions that were to enable a physical and mental spatial experience. This architectural staging also drew on insights from psychological esthetics and empathy theory from the last third of the nineteenth century, making use of the effect of colors, forms, and lines, as well as light and spatial disposition on the recipient, in order to achieve a previously unattained emotional control over the viewer. By means of detailed building descriptions, contemporary commentaries, and around 200 images, this book traces this architectural and psychological trail according to the key concepts of “empathy” and “abstraction.”