The awards were announced Monday by the Before Columbus Foundation, founded in 1976 by author Ishmael Reed.
Orange's debut novel was among the most acclaimed works of 2018. Stewart's "The New Negro: The Life of Alain Locke" won the Pulitzer Prize.
Other winners Monday include Halifu Osumare's memoir "Dancing in Blackness," Ángel García's poetry book "Teeth Never Sleep" and William T. Vollmann's nonfiction work on climate change, "Carbon Ideologies."
The educator and psychologist Nathan Hare was given a lifetime achievement award. His books include "The Black Anglo-Saxons" and "The Endangered Black Family."
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