Design drawings mediate between the world of ideas and the world of things, spanning the intangible and tangible.  However, contemporary technical architectural drawings, in establishing a direct relationship between the drawing and its object, tend to base this relationship on a visual paradigm that authenticates the visible physical world over the conceptual invisible world, including that of the designer's imagination. The result is that the drawing may become a reduced utilitarian tool for documentation, devoid of any meaningful value in terms of a kind of knowledge that could potentially link the visible and invisible. The imaginal drawing, assuming mundus imaginalis, is an ontological third world mediating between the invisible and visible worlds.  As such, it offers an alternative view of the architectural drawing. Inhabitants of this domain are subtle bodies that hold physical attributes (e.g. form, proportion, color), highly evocative, yet with no matter. Representing a world of similitudes, the imaginal is fundamental to the field of architectural representation, as it introduces a perspective in which the architectural drawing finds an ontological home, wherein the drawing becomes a true in-between territory, mediating between the invisible and visible. In this realm, the drawing becomes a subtle architecture in itself. Prevalent Islamic geometric architectural drawings, namely girih, which lend themselves to the imaginal, provide clues by which the drawing is recognized as an in-between. The geometric interlocking patterns they feature, the girih mode, represent a creative agent by which the built transcends the physical world and penetrates realm of spirituality. An examination the girih mode in its intellectual, imaginative, and physical contexts re-identifies these geometric drawings as a productive realm of consciousness. As an aperture to the imaginal, these architectural drawings open the door to a world of its own, wherein the drawing has a true subtle existence. In this view, the drawing starts from the domain of human imagination with the possibility of ascending to the realm of the intellect, while at the same time descending to the realm of the senses to guide the architect toward a built object. Seen this way, the imaginal drawing can offer an in-between state of being and becoming, a subtle matter, lighter than the building and denser than the idea"essentially representing a mode of consciousness involving the conscious imagination. / Ph. D.