Things Fall Apart, by Chinua Achebe
It's the most famous African novel there is, and I read it so long ago that I could no longer remember much of it, so I put Things Fall Apart on my Classics Club list. I probably understood it quite a bit better this time around!
The story of Okonkwo, a strong but unthinking man caught in the inevitabilities of change, is one that gives us plenty to think about. He is watching his traditions change and erode as white colonialists slowly take over the country. But you don't need a plot synopsis from me. It's hard to know what to say about books like this.
Things Fall Apart is such an extremely important book, and one that is very readable to boot; I would recommend that everyone read it.