In An American Friendship, David Weinfeld presents the biography of an idea, cultural pluralism, the intellectual precursor to modern multiculturalism. He roots its origins in the friendship between two philosophers, Jewish immigrant Horace Kallen and African American Alain Locke, who advanced cultural pluralism in opposition to both racist nativism and the assimilationist "melting pot." It is a simple idea—different ethnic groups can and should coexist in the United States, perpetuating their cultures for the betterment of the country as whole—and it grew out of the lived experience of this friendship between two remarkable individuals.

Kallen, a founding faculty member of the New School for Social Research, became a leading American Zionist. Locke, the first Black Rhodes Scholar, taught at Howard University and is best known as the intellectual godfather of the Harlem Renaissance and the editor of The New Negro in 1925. Their friendship began at Harvard and Oxford during the years 1906 through 1908 and was rekindled during the Great Depression, growing stronger until Locke's death in 1954. To Locke and Kallen, friendship itself was a metaphor for cultural pluralism, exemplified by people who found common ground while appreciating each other's differences. Weinfeld demonstrates how this understanding of cultural pluralism offers a new vision for diverse societies across the globe. An American Friendship provides critical background for understanding the conflicts over identity politics that polarize US society today.