Gerald S. Bernstein, a former art history professor with a knack for architecture and colloquial relationships with his students, died of pneumonia Jan. 8. The Newton resident was 70.Prof. Bernstein, or Gerry, as his family, friends and students knew him, joined the fine arts department in 1967. The Brooklyn native was a graduate of Adelphi University, and had previously taught at the University of Kansas and the University of Pennsylvania, where he received his Ph.D.

At Brandeis, Prof. Bernstein's classes were instantly popular. Betsy Phau '74, a theater major, took his art history survey class in the spring 1972 semester and formed a 34-year friendship with the professor.

"He would put the art in its historical time and show what the art was about organically, what it grew out of," Phau said of Prof. Bernstein's teaching style, which included political and historical context to the works reviewed in his class.

Prof. Bernstein's love of architecture manifested itself in his other classes and in his side ventures. In 1976 he founded Boston By Foot, a tour company that provides walking tours of downtown Boston.

"He was an incredible walker," his daughter Erica Nazzaro of Newton said. Leading groups through Beacon Hill, Back Bay and the North End, Professor Bernstein provided tens of thousands of the city's residents and visitors with another perspective on its long history.

As the authority on the campus's outward appearance, Prof. Bernstein was enlisted as the editor of "Building a Campus," a 1999 volume about Brandeis' varied architecture published for the 50th anniversary of the University's founding.

Phau, now a director of The Rose Art Museum and the University's arts council, which advises the school on its artistic curriculum, also recalled memories of tours led by Prof. Bernstein. During class reunions, one of the more popular activities would be a trip through the campus.

Prof. Bernstein never expressed love or hate for any particular building, Phau said, but he was a fan of the international style in which much of the campus was constructed and was loath to see original buildings altered.

"He was always saddened when buildings (such as the Sherman Dining Hall), had to be added onto, thereby ruining their architectural identity," Phau said.

In addition to Nazzaro, Professor Bernstein is survived by a son, Bobby of Key Biscayne, Fla.; another daughter, Sarah, a student at Brown University; and two grandchildren. He was the former husband of Marjori Bernstein and Susan M. Callaghan, both of Newton. A memorial service was held Jan. 10 in the Berlin Chapel. Burial was in Beth Israel Memorial Park in Waltham.