Richard Gray, who died in 2005, was a pioneer in the study of African history, focusing in particular, in his later years, on the religious history of the continent. For over twenty years he served on the Pontifical Committee of Historical Sciences and worked on a comprehensive study of the papacy and Africa. In undertaking this work he originally assumed that the critical initiatives came from within Catholic Europe or its missionaries. He soon discovered, however, that the initiatives came from African Christians: from Ethiopia, its Christian tradition stretching further than many parts of northern Europe; from Kongo, the first African kingdom to respond with a spontaneous enthusiasm to the Portuguese proclamation of the Gospel; from appeals to Rome by African Catholics who were attempting to reconcile their needs and their culture with the Christian laws brought to them by missionaries; and finally by slaves of African origin from the New World who were protesting against the appalling discrepancy between Christian principles and the practice of slave traders and owners. With Gray's work left unfinished, Lamin Sanneh, one of the leading scholars of World Christianity, has assembled the published essays which underlay this intended study. The result is