Quicksand (1928) by Nella Larsen
I've read this relatively slim novel a couple of times (as an undergrad, then as a grad student) and was drawn each time to Larsen's poignant criticism of American culture and beliefs about race. In Quicksand, Helga Crane, a mix of black West Indian and Danish, moves around the U.S. and Denmark, trying to find a place where she'll be accepted. In America, she suffers the indignities of racist propaganda and second-class citizenship, while in Denmark, she's treated as an exotic specimen, rather than as a human being. Her search for a literal and figurative home is a brilliant example of Harlem Renaissance literature.