John Pennethorne (1808-1889) was a nephew of John Nash and brother of Sir James Pennethorne, Architect to the Office of Works. The author toured Paris, Milan, Florence, Venice, Rome, Sicily, Athens, and Thebes to complete this study of ancient architecture, the main theme of which is the use of subtle curvature in Greek architecture. Extensive study allowed Pennethorne to conclude: that the colouring and ornamentation of Greek temples, as well as some aspects of their geometry, derived ultimately from Egypt; second, that there was no foundation for the conventional belief that Greek architectural design was absolutely rectilinear; third, that Greek temples were designed to be seen from certain points of view. Not all his beliefs have been accepted by later scholars. But his careful research, embodied in this book, made an important contribution to the understanding of the architecture of ancient Greece and of the importance of mathematics in determining architectural proportion.