William Clark is a professor of Art History at Queens College and at the Graduate Center, CUNY. He specializes in French medieval architecture, and his publications include Medieval Architecture, Medieval Learning: Builders and Masters in the Age of Romanesque and Gothic (1992). He has appeared in the PBS series "The Art of the Western World," which is regularly rebroadcast, and on a Nova program with Robert Mark. His major interests focus on the conceptual thinking of medieval builders, artists and patrons, as is revealed in the works of art, revival elements in medieval architecture, and the beginnings of architectural photography in Europe. He is the author of the popular Medieval Cathedrals (2006) ISBN: 0-313-32693-2.