Introduction Only prejudice, and a trick of the Mercator projection, prevents us from recognizing the enormity of the African continent. Covering nearly twelve million square miles, Africa is almost as large as North America and Europe bined. It is nearly twice the size of South America. As we mistake its dimensions, we also mistake its essential nature: the Dark Continent is mostly hot desert and open grassy plains. In fact, Africa is called the Dark Continent for one reason only: the vast equatorial rain forests of its central region. This is the drainage basin of the Congo River, and one-tenth of the continent is gi