Seymour Jacob Mandelbaum, 77, of Wynnefield, a professor of city and regional planning who challenged students with probing questions, died Wednesday, Jan. 23, of Parkinson's disease at Penn Hospice at Rittenhouse.

An innovative thinker, Dr. Mandelbaum used his post at the department of city and regional planning in the University of Pennsylvania's School of Design to spark debate.

"He was a legend in the department because of this role he played, asking these impossible-to-answer questions and pushing students to think through the answers in the narrowest and broadest senses," said colleague Eugenie L. Birch, Nussdorf professor of urban research.

"He wanted to know the moral, social, economic, and political implications. He made a lasting mark on those students."

Dr. Mandelbaum's Socratic method had an uncanny habit of foreshadowing events. In 2000, he asked students to posit from a planning standpoint what would happen if New Orleans were hit by a Category 3 storm.

"Whoever thought it would become a reality?" Birch said of Hurricane Katrina, which came ashore Aug. 29, 2005. "He asked the questions that were not on anyone's mind at the time."

A historian by training, Dr. Mandelbaum was born in Chicago and raised in New York before settling with his family in Philadelphia in the mid-1960s.

He earned his bachelor's degree from Columbia University and his graduate degrees from Princeton University. His Ph.D thesis on New York City in the 1870s led to his book Boss Tweed's New York.

Dr. Mandelbaum taught briefly at Carnegie Tech and Penn's Annenberg School for Communication before joining Penn's School of Design as a professor in 1967. He taught planning theory, communication policy and planning, international comparative planning, community design, and urban history.

Dr. Mandelbaum's interest was in the development of human communities, the moral orders that shaped them, and the flow of individuals and information through them.

He was the volume editor of Explorations in Planning Theory and served on the editorial boards of the Journal of Planning Education and Research, Journal of Architectural and Planning Research, Responsive Community, Journal of Planning Literature, and Town Planning Review.

 After becoming professor emeritus in 2004, Dr. Mandelbaum stayed on as editor of the Journal of Planning Education and Research until 2010, when he became ill.

His wife, the former Dorothy Rosenthal, said the two met as 18-year-old camp counselors.

He enjoyed vacationing with his family on Long Beach Island, N.J.

Surviving, in addition to his wife, are sons David and Judah; a daughter, Betsy; a sister; and six grandchildren. A brother died last year.

Services will be at 10 a.m. Friday, Jan. 25, at Joseph Levine & Sons, 4737 Street Rd., Trevose. Interment will be in Roosevelt Memorial Park. The family will return to the late residence.

Contributions may be made to the Parkinson's Disease and Movement Disorders Center, University of Pennsylvania, 330 S. Ninth St., Philadelphia 19107, or to the National Parkinson Foundation, 1501 N.W. Ninth Ave., Miami, Fla. 33136.