Witold Rybczynski (b. 1943) is a Canadian-American architect and writer. After teaching for more than twenty years at McGill University in Montreal, he currently serves as Emeritus Professor of Urbanism at the University of Pennsylvania. He is the author of more than 300 articles and eighteen books on cities, housing, architecture, and technology, including The Biography of a Building (2011) and Waiting for the Weekend (1991). He writes regularly for Slate magazine. His official website is www.witoldrybczynski.com.