This book is the revised and enlarged second edition of a biography of the missionary and linguist Johannes Rebmann (1820-1876), a Christian from Germany who worked in 19th-century East Africa. Rebmann was deeply influenced by the Movement of Pietism in his homeland Württemberg. He was trained to be a missionary in Basel, Switzerland, for the Anglican Church Missionary Society (CMS). From its base in London the CMS sent him to the Muslim-ruled and slavery-ridden Mombasa area of present-day Kenya. There he stayed for 29 years before returning home to Gerlingen near Stuttgart, blind and sick, soon to die. Rebmann was a faithful witness of Christ in word and deed. He experienced a lot of suffering and opposition, but was instrumental in establishing the Church in East and Central Africa. His lexicographical work facilitated succeeding missionaries. He compiled vocabularies of the Swahili and N(y)ika languages. Together with Salimini, a slave captured near Lake Nyasa (now Lake Malawi) by the Swahili Arabs, he made a dictionary of the 'Kiniassa', an important language in Central Africa, which is now usually called Chichewa.