“I am an aesthete,’’ Douglass Shand-Tucci once told the Globe. “What can I say?’’

Quite a lot, it turns out. His first major book, “Built in Boston,’’ was published in 1978. He followed it with a handful of lengthy volumes that illuminated the history of the city’s architecture, often focusing on details other writers ignored or overlooked. In the preface, he said he wrote “Built in Boston’’ because “so many of the buildings that moved me seemed to move no one else.’’

Among his own “architectural ‘first-loves’ ’’ were the Abbey Room in the Boston Public Library and the chapel at the Massachusetts Institute of Technology.

“One may stand in such places as these,’’ he wrote, “even if only in memory or imagination, pouring out one’s heart in the most extraordinary way toward something that — in just the same key — will always give back more than one could have imagined.’’

Mr. Shand-Tucci was having lunch with a friend at a Newbury Street restaurant on April 11 when he had a heart attack. He was 76 and lived in the Vendome on Commonwealth Avenue.

“He died doing one of his favorite things, having a conversation,’’ said Keith Morgan, professor emeritus of American and European architecture at Boston University, who had been another of Mr. Shand-Tucci’s regular lunch companions.

As a friend and as a writer, “he had an exceptional ability to understand connections,’’ Morgan said.

“He was one of the city’s leading historians,’’ Morgan added. “He cared deeply about Boston’s evolution, but he also wanted to pull away from the broad characterizations of what has formed the city and its identity to examine them critically and see what other layers and levels existed.’’

Mr. Shand-Tucci “has an incurable habit of looking at his surroundings and then trying to discover who built what, and why,’’ Walter Muir Whitehill, an author, historian, and former director of the Boston Athenaeum, wrote in a foreword to “Built in Boston.’’

The research Mr. Shand-Tucci conducted was unsparing. “I have read every damn dull biography of every damn dull Bostonian since 1850,’’ he told the Globe in 1979, not long after the first edition of “Built in Boston’’ was published.

Far less dull were lives like those of Isabella Stewart Gardner, the subject of his 1997 biography “The Art of the Scandal,’’ which The New York Times named a notable book of the year.

“The imagination of Isabella Stewart Gardner yielded a remarkable achievement in the museum to which she gave her name and treasure,’’ he wrote in an essay published in the Globe in 1990. “But it is an achievement easily overlooked. Because she was rich and famous, we are too willing to gape at her legacy, with dollar signs in mind. And because she was eccentric, there also is scarcely any story we will not credit, however much it sensationalizes and trivializes her. We seem relentlessly more interested in her means than in her ends. It is a losing battle, perhaps, for a historian to try to set the record straight.’’

Though he wrote biographies of Gardner and the architect Ralph Adams Cram, Mr. Shand-Tucci was just as fond of less celebrated parts of the city’s identity. Derided by some as “Boston’s weed,’’ the three-decker found a much-needed champion in Mr. Shand-Tucci.

“Shed a tear for the three-decker, the house Boston built for the world,’’ Globe critic Robert Taylor, while praising “Built in Boston,’’ wrote in a 1978 review. “Architecturally speaking, it’s an endangered species. If, however, the imminent demise of the three-decker leaves you dry-eyed, Douglass Shand-Tucci might persuade you to take another look.’’

Paul Douglass Tucci was born in Boston in 1941, a son of Dr. John H. Tucci, an anesthesiologist, and the former Geraldine Shand.

Mr. Shand-Tucci dispensed with his first name and, when he began publishing books after graduating from Harvard College in 1972, he added his mother’s maiden name to his last name.

“I got no closer to my father than the Harvard Club he was a member of so many years before me; he and my mother separated when I was 7; divorced when I was 9,’’ he wrote in “The Crimson Letter: Harvard, Homosexuality, and the Shaping of American Culture,’’ published in 2003.

He added that “like so many gays’’ it was his mother that “I thankfully depended on.’’ It was she who introduced Mr. Shand-Tucci to the Isabella Stewart Gardner Museum. His mother had graduated from Simmons College nearby and was a regular patron.

In 1998, Mr. Shand-Tucci told the Globe that with “The Art of the Scandal’’ he hoped to present Gardner as someone who “opened up the Boston of her day to people of other races, of other cultures,’’ rather than as the “quaint old Boston type.’’

Mr. Shand-Tucci “performs a true service in debunking the myths that shroud Isabella Stewart Gardner,’’ Taylor wrote in a Globe review. In the biography, Gardner “is a ministering angel to the marginal and dispossessed in Victorian Boston — gays, blacks, Jews, Quakers, feminists, immigrants of all nations. John L. Sullivan protects her carriage against mobs, John Singer Sargent and his homosexual circle of friends relish her gossip. She is the apotheosis of the politically correct.’’

And Mr. Shand-Tucci? “There are two Douglasses,’’ he said mischievously in a 2003 Times interview. “One respectable. One not.’’

While growing up in the Jones Hill section of Dorchester in his family’s 22-room Victorian house, he attended boarding schools in the United States and in Canada. Before transferring to Harvard, he attended Emerson College “briefly and ingloriously in the misguided belief that I was destined to be an actor,’’ he recalled in “Boston Bohemia: 1881-1990,’’ the first of his two volumes on Cram’s life and architecture.

For a time he wrote for the Boston Phoenix, and he had taught at Boston Architectural College and MIT, for which he wrote a campus guide called “MIT: An Architectural Tour.’’ He also had been the senior affiliate in the history of architecture at Harvard’s Eliot House.

Mostly he wrote at home in the Vendome, surrounded by paintings, antique furniture, family heirlooms, and books. He kept a rowing machine in a narrow hallway for daily exercise and wrote his books in longhand, often with a heavy felt pen on yellow pads. On days with fine weather, he sat by a bay window that overlooked two of his favorite buildings — Old South Church and the Hancock tower.

Recently, he was writing a book he planned to call “The Gods of Copley Square’’ that examined how institutions and events since the mid-19th century shaped and defined that key part of Boston.

Mr. Shand-Tucci leaves two brothers from his father’s second marriage with whom he had not been close, said Morgan, his executor.

A memorial service will be held at 3:30 p.m. Thursday in Trinity Church in Boston.

At times in his books, Mr. Shand-Tucci included asides about his life and how he had been guided by the example of his writing subjects.

“I feel people should understand me as I understand myself,’’ he said in 1998. “As I get older, I like to talk about people who have influenced me. My happiest pursuit is paying them back in this way.’’

Bryan Marquard can be reached at bryan.marquard@globe.com.