Archbishop Alexandre Le Roy was among the founders of the Catholic faith in Zanzibar and Tanzania. He became the fifteenth superior general of the missionary Congregation of the Holy Spirit (1896-1926). Not only was he fluent in Swahili, he was also a botanist and an anthropologist, as evidenced by the thick descriptions of the flora and fauna and the language, culture, and religion of the peoples he encountered. He has written a fascinating account of the beginnings of the faith in that part of...