Stanley Engerman, one of the authors of a deeply researched book that, wading into the fraught history of American slavery, argued that it was a rational, viable economic system and that enslaved Black people were more efficient workers than free white people in the North, died on May 11 in Watertown, Mass. He was 87.

His son David said the cause was myelodysplastic syndrome, a rare form of blood and bone marrow cancer.

In their two-volume “Time on the Cross: The Economics of American Negro Slavery” (1974), Professor Engerman and Prof. Robert W. Fogel used data analysis to challenge what they called common characterizations of slavery, including that it was unprofitable, inefficient and pervasively abusive.

They said they were not defending slavery. “If any aspect of the American past evokes a sense of shame,” they wrote, it’s the system of slavery.” But much of the accepted wisdom about it, they said, was distorted, or just plain wrong.

“Slave agriculture was not inefficient compared with free agriculture,” they wrote. “Economies of large-scale operation, effective management and intensive utilization of labor made Southern slave agriculture 35 percent more efficient than the Northern system of family farming.”

They insisted that the typical slave “was not lazy, inept and unproductive” but rather “was harder working and more efficient than his white counterpart.” They contended that the destruction of the Black family through slave breeding and sexual exploitation was a myth, and that it was in the economic interest of plantation owners to encourage the stability of enslaved families.

They also wrote that some slaves received positive incentives, such as being elevated to overseers of work gangs, to increase their productivity.

The book attracted a lot of attention, including a rave review by the economist Peter Passell in The New York Times. “If a more important book about American history has been published in the last decade, I don’t know about it,” he wrote. He described the work as a corrective, “a jarring attack on the methods and conclusions of traditional scholarship” on slavery.

Not every review was as kind. Thomas L. Haskell, writing in The New York Review of Books in 1975 about three books that challenged the findings of “Time on the Cross,” called it “severely flawed.” Some historians criticized its relatively benign portrayal of slave life.

“We thought there’d be a lot of discussion within the history profession for a while, but the public reaction is something else,” Professor Engerman told The Democrat and Chronicle of Rochester in May 1974.

When he and Professor Fogel — who would share the Nobel in economic sciences with Douglass C. North in 1993 — appeared on the “Today” show, Kenneth Clark, the prominent Black sociologist, accused them of portraying slavery “as a benign form of oppression.”