Henry Edward O ́Neill was British Consul in Mozambique from 1879 to 1889. He completed thirteen exploratory journeys in northern Mozambique, including the first exploration of the Makua and Lomwe countries between Mozambique Island and Lake Malawi. This recreation of the book, which he never published, makes available for the first time a large body of information on the peoples of northern Mozambique (a region still little researched), on the history of the slave trade in the western Indian Ocean and on the expansion of Portuguese rule and the resistance to it by powerful local communities. The Introduction includes the first ever biographical study of O ́Neill and his contribution to African exploration.