Attempts to compress a continent's history in 370-odd pages, and so it gets bogged down in the first half with a hard-to-follow succession of names and places (without enough maps). For a primer on African history, it's good, living up to its name and all, and on how Africa got to be in its current state, it's pretty enlightening.
Basically, like a lot of the rest of the world, there were a number of regions in Africa that were more advanced than Europe up till at least the fifteenth century. The northern half of Africa got integrated into the very advanced Islamic world through trade back when Europeans were digging potatoes out of the ground with six-toed feet, and at first contact European traders were actually importing West African cloth, for example. But not having Europe's geography meant not having as much pressure to develop ships (except Eastern Africa, which was trading as far as China before Portuguese barbarians sacked its main cities) and weapons. The killer for African development was the slave trade, which beyond depopulating the continent by some tens of millions was destructive by hamstringing its manufacturing base. First, trading human raw material for manufactured goods - aka comparative advantage - worked as it always has in history. It had a negative effect (contrary to the current orthodoxy in economics) by forestalling any further development in metalwork and handicrafts. Plus, the people shipped off to Europe and the Americas were the most able-bodied men and women, skilled in metalworking and tropical agriculture. Not to mention the devastation that constant slave raids would wreak all around Africa's coasts and into its interior. (Even the east coast, which was for a long time under Arab Muslim control after they kicked out the Portuguese and reestablished the trade routes that the more barbaric foreigners had ruined.)
Funnily enough, once Europe was strong enough to actually invade Africa it did so with the best of intentions - to stop the slave trade. Gee, aren't humans great? Whenever any bunch of them engages in some extremely evil enterprise, they do so with the most laudable of intentions, like the Japanese freeing Asia from the bondage of European imperialism, or the U.S. bringing freedom and democracy to the oppressed like the British before them brought civilization and progress to the savages.