William Barclay Parsons (April 15, 1859 - May 9, 1932) was a famous American civil engineer. He founded the firm that became Parsons Brinckerhoff Quade and Douglas, one of the largest american civil engineering firms.
He was also Chief Engineer of the New York Rapid Transit Commission, and was responsible for the construction of the Interborough Rapid Transit (IRT) subway line. A part of 158th Street in Queens New York City was named after him as Parsons Blvd.
His books include:
An American Engineer in China (1900)
Engineers and Engineering of the Renaissance (1939)