“He wrote about heroic black women, slave rebellions and antislavery movements when discussing such matters was dangerous and seen as unpatriotic,” Jesse Weaver Shipley, a professor of African and African-American studies and oratory at Dartmouth College, said in an email.
Among Mr. Katz’s other books were “The Black West” (1973) and “Black Indians” (1986).
“When whites were sending out posses, Native Americans were extending the hand of friendship,” Mr. Katz told The Times in 1994. “Almost every Afro-American family in the United States has a Native American branch to its family tree, from Michael Jackson to Jesse Jackson, from Frederick Douglass to Langston Hughes.”
Mr. Katz was born Loren Paul Katz on June 2, 1927, in Brooklyn to Bernard and Madeline (Simon) Katz, whose own parents were Jewish immigrants. Ben Katz, as he was known, besides being a commercial art director, was an ardent leftist; Madeline Katz, a former championship diver, died several weeks after Loren was born. His stepmother, Phyllis (Brownstone) Katz, was an editor at Parents magazine.
Mr. Katz chose his pen name, Dr. Lehman said, because he had adopted the nickname Bill (his mother was known as Billie) and decided that William Loren Katz sounded more scholarly than Loren Paul Katz.
In addition to Dr. Lehman, whom he married in 1994, Mr. Katz is survived by a daughter, Naomi Katz, from a previous marriage, which ended in divorce; a granddaughter; and a younger stepbrother, Jonathan, whom he mentored and who wrote the trailblazing book “Gay American History” (1976). A son, Michael, died earlier.
Mr. Katz grew up in Greenwich Village and was in the first graduating class of the private, progressive Elisabeth Irwin High School in Lower Manhattan. He then joined the Navy and served in the Pacific at the end of World War II.