What is the theme in Cane by Jean Toomer?

This book deals with the issue of race on several different levels. Most obviously, there is the way that blacks are treated within American society, both in the South and in the North. In the South, the element of danger is always present. For instance, Becky is rejected by both blacks and whites for the crime of having crossed the color line, having sex with a black man and becoming impregnated by him