Dr. David Livingstone was a celebrity in his day. The reporter who set out through Africa to find him after a two-year silence prepared his famous line for when they finally met: "Dr. Livingstone, I presume?" He found him working and serving the people of Africa that Livingstone dedicated his life to.
Livingstone was a missionary, medical doctor, and explorer – and a huge celebrity in his day. He wrangled with mission boards and was difficult to get along with. He left his family for years at a time. He sought to end the slave trade and freed many. His explorations were not only significant geographically, they also opened the way for missionaries who followed him to the continent.
Livingstone wrote his first manifesto, a 400-page book called Missionary Travels and Researches in South Africa. It is still an important source for reconstructing the precolonial history of Africa. It was an immediate bestseller, selling 70,000 copies. As historian Timothy Holmes says in Journey to Livingstone (1993), it had something for everyone: "The Christian's faith in God is strengthened by the author's very survival of every imaginable danger. The abolitionist is inspired by the prospect of stopping the slave trade. Medical men are intrigued by Livingstone's approach to disease and the value of his treatment for fever."
The reporter, Henry Stanley, who found Livingstone became a Christian because of him and took up his work after his death.
Stanley described Livingstone as a "truly pious man—a man deeply imbued with real religious instincts. His religion … is of the true, practical kind, never losing a chance to manifest itself in a quiet, practical way—never demonstrative or loud. It is always at work, if not in deed, by shining example."
Livingstone's tacit evangelism touched Stanley, who had arrived in Africa "as prejudiced against religion as the worst infidel in London." Livingstone had truly left all to follow Christ, and his model of dedication converted Stanley. After Livingstone's death, Stanley stepped up to continue his fantastic voyages.
You can read more about this intriguing man.