Historians Keisha N. Blain and Ibram X. Kendi began working on “Four Hundred Souls: A Community History of African America, 1619-2019” in 2018. The best-selling collection, co-edited by Kendi, author of “How to Be an Antiracist,” and Blain, author of “Set the World on Fire: Black Nationalist Women and the Global Struggle for Freedom,” features 80 short historical pieces, personal essays, stories, and 10 poems by prominent Black writers. Told in five-year increments, the work offers a varied look at four centuries of the African American experience.