Architecture is the only art of habitable space; it is the business of the architect, and of the architect alone, to give to such space, experienced four-dimensionally, visual meaning. Therefore, says Philip Thiel, visual education should have a central place, next to design itself, in the curriculum of any school of architecture, and to be effective it must be enlarged beyond the time-honored exercises of freehand sketching and rendering. He goes on to show how a program in visual education using other graphic processes (notably photography) may be developed, in sequence and in depth, so as to supply the kind of unique preparation that an unique profession demands