The book for which Adelaide M. Cromwell is best known had its seeds in her graduate-student days some 70 years ago, when she noted that a key part of Boston’s African-American history had gone largely unrecognized.
“When I chose the Negro upper class as the topic for my dissertation in the late 1940s, few students believed such a class existed within the black community. Interest and research had been focused on the black poor,” she wrote in the preface to her 1994 book “The Other Brahmins: Boston’s Black Upper Class 1750-1950.”
She was undeterred: “I was convinced of not only the existence but also the importance of this group.”
Dr. Cromwell, who was the first African-American faculty member hired by Smith College, and went on to be a sociology professor at Boston University, where she founded the African American Studies program, died June 8. She was 99 and had lived in Brookline for many years.
Among her other books was a history of her own accomplished family. Her relatives included Otelia Cromwell, an aunt who was Smith’s first African-American graduate, and Edward Brooke, a cousin who was the first African-American popularly elected to a US Senate seat from Massachusetts.
“The story of the Cromwell family is one of slavery, emancipation, and freedom,” she wrote to open the first chapter of “Unveiled Voices, Unvarnished Memories: The Cromwell Family in Slavery and Segregation, 1672-1972,” which was published when she was 87.
Ever a precise historian, she added that her family’s history “has been passed on by word of mouth but has been altered and expanded by the less romantic, irrefutable facts of accurate documentation.”
At Smith, the College Hall flag was lowered to half-staff earlier this month in honor of Dr. Cromwell’s groundbreaking accomplishments. Kathleen McCartney, Smith’s president, posted a tribute and condolences online, noting that Dr. Cromwell had graduated from the college in 1940, before returning to break the faculty color barrier.
Dr. Cromwell “was an expert on the black elite in America and in Africa,” Louis Chude-Sokei, a professor who directs BU’s African American Studies program, said for an online tribute the university posted.
She had undertaken her doctoral study of the role social class played in the black community in the 1940s, “a comparatively auspicious period to begin research on social stratification,” she wrote in “The Other Brahmins,” which was published in 1995.
“Stratification had been an interest of mine from undergraduate days,” she added. “Perhaps my having come from Washington, D.C., and having had an opportunity to live in Philadelphia before moving to Boston had sharpened my perception of the differences between what might appear to be identical black communities, especially reflected in the composition of the upper class.”
Yet Dr. Cromwell knew that as a scholar and writer, she was taking on a subject many prefer to avoid, regardless of their background.
“Class has always been a no-no word in our society,” she said in a 1994 Globe interview. “When I was teaching at Smith, I would ask the students to identify themselves by class. Everybody would say ‘middle class,’ even if it was obvious that they weren’t. You have to be in a tight little group before it really comes out, and then it’s pretty apparent.”
That was also true, Dr. Cromwell added, among African-Americans.
“You won’t get blacks to say, ‘I’m upper class.’ It’s more like: ‘I’m not that type of person,’ or ‘I don’t live that kind of life,’ or ‘I go to this club or that resort,’ ” she told the Globe. “The only difference is that the white world has more barometers. You can just pick up that Social Register, and you’re either in it or you’re not in it. Blacks don’t have anything that’s comparable.”
Born in Washington, D.C., in 1919, Adelaide McGuinn Cromwell was the only child of John Wesley Cromwell Jr. and Yetta Mavritte.
“The circumstances of my mother’s youth were especially conducive to promoting an interest in family history,” her son, the writer Anthony Cromwell Hill of Cambridge, wrote in the introduction of “Unveiled Voices.”
She grew up in a townhouse on 13th Street in the city’s Northwest quadrant, in a household that included three of her father’s sisters — among them Otelia Cromwell, whose path she followed to Smith and into academic scholarship. Otelia was the first African-American woman to receive a doctorate from Yale University.
Dr. Cromwell’s mother was a homemaker, and her father was a certified public accountant and a high school math teacher. Her paternal grandfather, John Wesley Cromwell Sr., was “a newspaper proprietor, historian, lawyer, civil servant, and educator” in Washington who created an archive of family historical records that Dr. Cromwell would use years later for her book on her family, Anthony Hill wrote in the “Unveiled Voices” introduction.
After finishing Paul Laurence Dunbar High School in Washington at 16, Dr. Cromwell went to Smith, from which she graduated Phi Beta Kappa with a bachelor’s degree in sociology.
While there, she launched her scholarly career in 1940, writing an article for the Journal of Heredity about piebaldism — a genetic trait that leads to a white forelock and depigmented patches of skin, which had appeared in three generations of one branch of her family.
Subsequently, she received a master’s in sociology from the University of Pennsylvania and a certificate in social work from Bryn Mawr College, her son wrote in the introduction.
In 1943, she married Henry Hill, a chemist with whom she had one son. Their marriage ended in divorce, as did her second marriage, to Philip H. Gulliver, an anthropology professor.
Dr. Cromwell was a pioneering African-American instructor at Hunter College in New York City before joining Smith’s faculty and later moving to Boston University. She graduated from Radcliffe College with a doctorate in sociology and was a cofounder of BU’s African Studies Center, where her work led her to visit Africa several times for research.
Among the other books she wrote was “An African Victorian Feminist: The Life and Times of Adelaide Smith Casely Hayford, 1848-1960.” Dr. Cromwell’s biography of the Sierra Leone educator was published in 1986.
With her teaching and her work directing BU’s African American Studies program, however, Dr. Cromwell remained focused on mentoring students and aspiring scholars.
“The most important thing about my mother is that she was a very devoted educator and nurturer of people,” her son, who is Dr. Cromwell’s only immediate survivor, said in an interview.
A memorial service for Dr. Cromwell will be held at 1 p.m. Nov. 5 in Marsh Chapel at Boston University.
Over the years, she received honorary degrees from several colleges, including from Smith.
Along with documenting the history of her family and of Boston’s African-American Brahmins, and serving on numerous governmental commissions and academic panels, Dr. Cromwell worked to preserve key, Greater Boston historic sites that are significant to African-Americans.
In 2015, when she was 95, Secretary of State William Galvin recognized her work with a historic preservation award from the state Historical Commission.
Despite her age, she had told the Globe several years earlier, “I’m always finding something that needs doing.”