Things Fall Apart by Chinua Achebe

 

This is a short novel, and a pretty straightforward one--its message is barely in the subtext. The people of Africa were not perfect, and neither were their cultures; the arrival of Europeans did nothing to improve the lot of the people or the shape of their cultures. The fact the primary POV character in this novel is someone it's hard to call a particularly good person arguably makes that message all the clearer. It's a beautifully-written novel, does a good job of conveying the experience of living in that culture to a reader who has no points of reference. I can see why it regularly gets assigned in schools.