This course examines the history, theory and practice of parallel (orthographic) and central (perspective) projection. The objective is to provide the tools to imagine and represent with precision, dexterity, and virtuosity a continually expanding repertoire of three-dimensional architectural form. The focus of the lectures will be twofold: first, to trace key historical developments of projection in architecture from the Renaissance through the Enlightenment into the 20th century, and second, to explain the comprehensive codification of descriptive geometry and the means by which it is practiced. We will see that projective systems have effected relationships between masons, carpenters, engineers, mathematicians, cartographers, painters, and architects. The impact of the computer on architecture\’s perennial oscillation between the three and two dimensions of projection will come into focus. The representation of objects as we see them and their measured description, two tasks that are conventionally distinguished in architectural drawing, will be shown to have been unwittingly, in many respects, mutually determined and transformed.This course, 2122, was previously offered as 2102M2.