The Black Diaspora tells the enthralling story of African-descended people outside Africa, spanning more than five centuries and a dozen countries of settlement, from Britain, Canada, and the United States to Haiti, Guyana, and Brazil. Ronald Segal's account begins in Africa itself, with the cultures and societies flourishing there before the arrival of the Atlantic slave trade, which transported over ten million people to the Americas, after killing at least as many in their procurement and passage.

He examines the extent of the profits made through the trade by merchants, manufacturers, investors, and planters, along with the racist ideology that developed as whites strove to rationalize an enormous economic dependence.

Segal describes the various ways in which the system of slavery developed and provides the most comprehensive account to date of the resistance by the slaves themselves, from escape and arson to guerrilla warfare and revolution. When emancipation finally came, the former slaves were left in the fetters of poverty and discrimination. Segal details the course of the struggle against colonial rule and the racial oppressions of self-styled democracies.

In recounting his own travels through the Diaspora, he shows the continuing plight of peoples confined by the consequences of the past and the prejudices of the present: racked by violence, as in Jamaica and the ghettos of America; denied the right to assert their sense of identity, as in Cuba; acknowledged only to be repudiated, as in Brazil.

Yet this is also, Segal reveals, a Diaspora of wondrous achievement. It has immeasurably enriched world culture in music, language and literature, painting, sculpture and architecture; has done much to make sports a form of art; and has invested Western culture with the ecological reverence derived from its African source. Segal argues that the black Diaspora has a unique destiny, infused by the love of freedom that is its creative impulse.