Neil Leonard, 84, a pioneering jazz historian and critic and a retired professor of history at the University of Pennsylvania, died Sunday, Nov. 13, at Hahnemann University Hospital after a stroke. A memorial service is scheduled for Sunday, Feb. 23, at Penn.

Mr. Leonard's doctoral thesis, Jazz and the White Americans: The Acceptance of a New Art Form, became a groundbreaking book on cultural awareness of jazz. It was published in 1962 by the University of Chicago Press.

He was on the faculty at Penn from 1961 until 1990s. He worked in the American civilization department and later in the history department.

Mr. Leonard was born on Dec. 3, 1927 in Cambridge, Mass., and was raised in nearby Newton. He earned a bachelor's degree in history at Colby College and a doctoral degree in American studies from Harvard College.

He served in the Army during the Korean War, earning the rank of corporal. In 1954 he married Dorothy Washburn Leonard. The couple had four children. They lived in Lower Gwynedd for a long time, later moving to Center City.

His book drew wide acclaim over the years. John Gennari, an associate professor of English at the University of Vermont who studied with Mr. Leonard at Penn, praised Mr. Leonard's book as groundbreaking.

The author of Blowin' Hot and Cool: Jazz and Its Critics, Gennari wrote that Mr. Leonard's book "was the first systematic, analytical account of the culture war that jazz triggered in 1920s America, a war of ideas and passions in which a cult of true believers embraced jazz as the salvation and redemption of Western civilization, while the rearguard of latter-day jeremiahs saw it as a fatal sign of degeneration and damnation."

Francis Davis, a local jazz critic and former adjunct professor at Penn, said Mr. Leonard was "a great guy, a good writer, and a good teacher."

Davis described Mr. Leonard's book as pioneering "in terms of looking at jazz in what then would have been considered a very academic way. ... He was a pioneer in that sense."

Mr. Leonard's son Devin said his father was "a great father, but he was also very intellectually well-rounded."

He noted that Mr. Leonard learned to speak German after he retired and that he went to Germany every summer. Mr. Leonard also enjoyed summer visits to Swans Island, Maine.

Devin Leonard said his father instilled in him and his brother, Neil, an appreciation of jazz, noting that both became jazz musicians.

He said that during Mr. Leonard's last days in the hospital, "We played him Louis Armstrong and we played him Lester Young and Billie Holiday. He died listening to the music that he loved and turned us on to."

In addition to his wife and sons, Mr. Leonard is survived by son Chris and daughter Amy, and seven grandchildren.