Alfred Abraham Knopf, Jr. (June 17, 1918 – February 14, 2009) was one of the founders of Atheneum Publishers in 1959.
He was the only child of publisher Alfred A. Knopf, Sr. and Blanche Wolf. He was born in White Plains, New York, on June 17, 1918. At 7, in 1925 he was sent to a boarding school, first at the Riverdale Country School, in the Bronx, New York. From 1933 until 1937 he attended Phillips Exeter Academy.
The summer after he graduated from Exeter he ran away from home, despondent over being turned down by Princeton University. Following a police search, he was found in Salt Lake City, Utah.
During World War II, Knopf joined the Army Air Force and the Mighty Eighth Air Force. During his time in the service, he piloted the B-22 Bomber "Rough Buddy" through almost 100 missions alongside Engineer Richard E. Morton.
In 1952, he married Alice Laine. They had three children, Alison, Susan and David A. Knopf.
He was one of the founders of Atheneum Publishers in 1959. He died on February 14, 2009.