The cause was heart disease, according to his son, Kenneth Jr.
Stampp was the author of "The Peculiar Institution: Slavery in the Ante-Bellum South," a 1956 book that marked a turning point in historians' treatment of slavery. Rejecting the moonlight-and-magnolias mythology that inspired such stereotypes as the benevolent plantation owner and the smiling black mammy, he concluded that slavery was in fact a "most profound and vexatious social problem," a radical view in an America that had just begun to experience the tremors of the modern civil rights movement.
Labeled a revisionist by critics, he offered formidable scholarship that challenged that of the previous generation of historians, particularly by showing how the profit motive drove planters to control slaves.
He also showed how slaves resisted their bondage, not only through rebellion and escape but also through more passive methods, such as work slowdowns and breaking tools.
"He essentially recognized the humanity of African Americans," said Pulitzer Prize-winning historian Leon Litwack, a UC Berkeley professor emeritus who studied under Stampp in the early 1950s.
"What his book asked us to do was view slavery through the eyes of the slave as well as through the eyes of the slaveholders. . . . The voice of slaves could no longer be denied."
Published the year after Rosa Parks' historic refusal to move to the back of a segregated bus, Stampp's landmark book was sometimes seen as a product of the civil rights movement that Parks sparked. But his unorthodox critique of slavery had begun to develop at least a decade earlier, long before Parks and the Rev. Martin Luther King Jr. began to make headlines. And his sense of injustice had probably taken root even earlier, during a childhood marked by family upheaval.
He was born in Milwaukee of German stock on July 12, 1912. When he was about 6, his father moved to Chicago to learn naprapathy, a form of natural healing similar to chiropractic.
To support him and a younger sister, his mother went to work in a grocery store and moved in with her parents, taking with her the daughter but sending Stampp to live with an aunt. Shuffled from one relative to another for the next couple of years, he endured a Dickensian misery.
Several decades later, he recalled the sense of abandonment that drove him to roam the streets alone one night. "I thought that night: I can't depend on my parents. I'm going to have to look out for myself," he recalled in a 1996 oral history. "In a way, it was a horrible experience, but it was, at a very young age, a maturing experience."
He did well enough in school to attend the University of Wisconsin, where he earned a bachelor's degree in 1935, a master's in 1937 and a doctorate in 1942. In 1946, after short stints teaching at the University of Arkansas and the University of Maryland, he accepted an assistant professorship at UC Berkeley.
By the time he joined Berkeley's faculty, he was well-versed in the history of slavery, particularly the anti-slavery movement, the subject of his master's thesis.
In the American history classes he taught, he lectured extensively on slavery, relying upon his own research and what was then considered the standard text, University of Michigan historian Ulrich B. Phillips' "American Negro Slavery," published in 1918.
Phillips, a Southerner by birth, portrayed plantation owners in a largely favorable light as a civilizing influence on their African slaves. Stampp's lectures on slavery "were really a refutation of U.B. Phillips. That was kind of easy to do," Stampp said in the oral history.
After he finished his first book, "And the War Came" (1950), about the Civil War, Stampp decided to write his own history of slavery. When "The Peculiar Institution" was published, it was "not terribly well reviewed" in mainstream journals, Litwack recalled, challenging as it did the prevailing accounts by Phillips and others.
However, within a few years, Stampp's work "became the generally accepted account of slavery, and the paperback edition found its way into classrooms throughout the nation, even the Deep South," John G. Sproat, a distinguished historian of the South who died last year, wrote in a 1998 essay.
The power of Stampp's book stemmed from its rich documentation -- which included narratives by fugitive slaves, antebellum newspapers, court records and slave owners' correspondence -- and its literary style. "But it was also in complete accord with the changing temper of the times in questions of race and civil rights," Sproat wrote, "and it is fair to say that it helped immensely to change the racial perceptions of a generation of young Americans."
Stampp joined a group of historians who traveled to Selma, Ala., in 1965 to participate in the civil rights march to Montgomery led by King. That year, he also published "The Era of Reconstruction, 1865-1877," an examination of the period following the Civil War, in which he again challenged historical orthodoxy, this time with a bracing analysis of the North's "Radical Republicans" and their widely maligned efforts to achieve equality for blacks after emancipation.
In 1993 he received $40,000 as the recipient of Gettysburg College's Lincoln Prize, which honored him for his lifetime contributions as a historian of the Civil War era. His other noteworthy books include "The Imperiled Union" (1980) and "America in 1857: A Nation on the Brink" (1990).
Stampp's first marriage ended in divorce, and his second wife, Isabel Peebles Brown, died in 1996. In addition to his son, he is survived by his companion, Jean Working of Oakland; daughters Sara Katherine Stampp of Berkeley, Jennifer Elizabeth Stampp of El Cerrito and Michele S. Macartney- Filgate of Toronto; and four grandchildren.
Memorial donations may be sent to the Isabel B. and Kenneth M. Stampp Fund for the San Francisco Symphony, c/o the San Francisco Symphony, Davies Hall, San Francisco, CA 94102.