"In 1770, on the eve of the American Revolution, African American slavery was legal and almost unquestioned throughout the New World. The ghastly slave trade from Africa was still expanding and for many decades had been shipping five Africans across the Atlantic for every European immigrant to the Americas. An imaginary “hemispheric traveler” would have seen black slaves in every colony from Canada and New England all the way south to Spanish Peru and Chile. In the incomparably rich colonies of the Caribbean, they often constituted population majorities of 90 percent or more. But in 1888, one hundred and eighteen years later, when Brazil finally freed all its slaves, the institution had been outlawed throughout the Western Hemisphere. This final act of liberation, building on Abraham Lincoln’s emancipation achievement in the American Civil War, took place only a century after the creation of the first antislavery societies in human history—initially small groups in such places as Philadelphia, London, Manchester, and New York. The abolition of New World slavery depended in large measure on a major transformation in moral perception—on the emergence of writers, speakers, and reformers, beginning in the mid-eighteenth century, who were willing to condemn an institution that had been sanctioned for thousands of years and who also strove to make human society something more than an endless contest of greed and power."