Nothing is "pure" in America, and, indeed, the rich ethnic mix that constitutes our society accounts for much of its amazing vitality. Werner Sollors's new book takes a wide-ranging look at the role of "ethnicity" in American literature and what that literature has said--and continues to say--about our diverse culture. Ethnic consciousness, he contends, is a constituent feature of modernism, not modernism's antithesis. Discussing works from...