UP ON THE ROOF: Photographer, pilot, and architect Alex MacLean has made a career of viewing landscapes from above. Shown here shooting an angle of New York City’s rooftops, he was the most recent speaker at the Princeton Public Library’s “Spotlight on the Humanities” architecture series.

Last Wednesday, people attending a lunchtime lecture at Princeton Public Library were given a rare glimpse of New York City. A bird’s eye view of Manhattan and Brooklyn rooftops, provided by pilot and photographer Alex MacLean, revealed surprising “roofscapes” containing lush gardens and geometric, agricultural patterns. The audience, clearly engaged by Mr. MacLean’s commentary as he projected views from his book Up on the Roof: New York’s Hidden Skyline Spaces, murmured repeatedly in surprise.

The gathering was the most recent in the library’s Spotlight on the Humanities Series focused on architecture. Begun earlier this year with talks by Princeton architecture professor Esther da Costa Meyer, the library’s designer Nicholas Garrison, and architect and dean emeritus of the Princeton University School of Architecture Robert Geddes, the series will continue with University Architect Ronald McCoy on January 17, Princeton based architect Michael Graves on February 13, and author Siobhan Roberts, whose book Wind Wizard is about Alan Davenport, considered the father of modern wind engineering, on February 26.

“It’s a wonderful series,” says Janie Hermann, the library’s programming director, following Mr. MacLean’s presentation. “People were just thrilled. And Alex sold almost a whole box of his books.”

The series is funded by contributions the library receives from the National Endowment for the Humanities. “I came up with the Spotlight on the Humanities because we had been getting requests for more daytime programming,” Ms. Hermann continues. “That’s challenging. But I realized that we would probably attract a crowd if we did scholarly lectures. I thought a lot of people in this town, some of whom are retired and some of whom are working, would hopefully come during their lunch break. And we’ve had a minimum of 40 or 50 people each time.”

Mr. MacLean is an architect who has flown his plane over most of the United States to document the landscape. His talk last week followed one the previous day at New York’s Mid-Manhattan Library. The latest book, published by Princeton Architectural Press, shows how changes to the city’s diverse rooftops are making the city more livable and sustainable. Photographs show not only green spaces but also water towers, swimming pools, tennis courts, restaurants, and sweeping works of art meant to be seen from above.

A committee including Ms. Hermann, Princeton University professor Stanley Katz, and Princeton University Art Museum Curator of Education Caroline Harris helps decide about programming for the series. Ms. Hermann found Mr. MacLean after reading a review of Up on the Roof. “I looked at his website and saw that he did public speaking,” she says. “So I reached out to him and he was happy to come.”

Next up is Mr. McCoy, whose talk is titled “Creating Place at Princeton.” The presentation will focus on “place-making” in architecture and landscape design, and how the Princeton campus balances innovation with a lasting sense of place. Mr. Graves, an internationally known architect whose most prominent local building is the Arts Council of Princeton across the street from the library, will discuss his work when he is featured in the series. Ms. Roberts will talk about her book, which investigates how wind navigates the obstacle course of the earth’s natural and built environments, and how when not properly heeded, causes damage — particularly appropriate considering the recent devastation of Superstorm Sandy.

Audiences meet in the library’s Community Room, where coffee and cookies are served, and attendees are welcome to bring a brown bag lunch. “The idea is to do this once or twice a year, depending on topics and availability,” says Ms. Hermann. “We’re very excited about it and the response has been very positive so far.”