An excellent adventure novel - imagine Indiana Jones in more genteel Victorian times. The idea of a lost civilization of white people in the middle of Africa must have seemed like a British Colonial dream. The author, however, gives a voice to the idea that too much civilization is not always such a good thing.
I gave it a 4 because there are a few long descriptive passages that might seem a bit tedious to the modern reader.
All in all, though, a great read.