Ulrich Bonnell Phillips (November 4, 1877 – January 21, 1934) was an American historian who largely defined the field of the social and economic studies of the history of the Antebellum South and slavery in the U.S. Phillips concentrated on the large plantations that dominated the Southern economy, and he did not investigate the numerous small farmers who held few slaves.

He concluded that plantation slavery produced great wealth, but was a dead end, economically, that left the South bypassed by the industrial revolution underway in the North.

Phillips concluded that plantation slavery was not very profitable, had about reached its geographical limits in 1860, and would probably have faded away without the American Civil War, which he considered a needless conflict.

Phillips argued that they provided adequate food, clothing, housing, medical care and training in modern technology—that they formed a "school" which helped "civilize" the slaves.

In 1911, Phillips moved to the University of Michigan where he taught until 1929 when he left to teach at Yale as Professor of American History until his death in 1934.

Today, as in Phillips' lifetime, scholars again commonly acknowledge the value of many of his insights into the nature of the southern class structure and master-slave relationships.

"[6] In his own right, Genovese recognized in Phillips' work, as many of his colleagues chose to ignore, that master-slave relationships were complex, multi-faceted, more often negative, exploitive, and dehumanizing, yet provided very limited opportunities for some bondsmen to earn cash, travel outside the plantation situation, and enhance their personal values.

As the historian Herbert Gutman noted, the Phillipsian answer was that slavery lifted the slaves out of the barbarism of Africa, Christianized them, protected them, and generally benefited them.

They said Phillips had defined the treatment issue and his most severe critics had failed to redefine it: By compiling instances of the kindness and benevolence of masters, Phillips proved to his satisfaction that slavery was a mild and permissive institution, the primary function of which was not so much to produce a marketable surplus as to ease the accommodation of the lower race into the culture of the higher.

Establishing and maintaining this domination--creating the system of racial segregation and African American disfranchisement known as Jim Crow--has remained a preoccupation of southern historians.In his review of Complicity: How the North Promoted, Prolonged, and Profited From Slavery by Anne Farrow, Joel Lang and Jenifer Frank, the historian Ira Berlin wrote, "Slavery in the North, like its counterpart in the South, was a brutal, violent relationship that fostered white supremacy.

"[12] John David Smith of North Carolina State University argues:[13] [Phillips was] a conservative, proslavery interpreter of slavery and the slaves ...

His basic arguments—the duality of slavery as an economic cancer but a vital mode of racial control—can be traced back to his earliest writings.

Less detailed but more elegantly written than American Negro Slavery, Phillips's Life and Labor was a general synthesis rather than a monograph.

In 1929 Yale University in New Haven, Connecticut, appointed Phillips professor of history.Phillips contended that masters treated slaves relatively well.

[18][19] For a comprehensive annotated guide see Fred Landon and Everett E. Edwards, "A Bibliography of the Writings of Professor Ulrich Bonnell Phillips," (1934).