Amazing Grace is lovely Christian hymn that we all know and can probably recite the first two lines no problem. Interesting that the man who penned the hymn was a wealthy British slave trader who found God, wrote the hymn and then joined the anti-slavery cause.
Bury The Chains by Adam Hochschild is a wonderful book about the small number of brave people in Britain who fought to abolish slavery at a time when Britain was wealthy and powerful in the world because of it.