When the American reporter Henry Morton Stanley stepped out of the jungle in 1871 and doffed his pith helmet to the Scottish missionary-explorer Dr. David Livingstone, his greeting was to take on mythological proportions. But do any of us really know what his words meant at the time--and what they have come to mean since?

Far from meeting in a remote thicket in "Darkest Africa," Stanley met Livingstone in the middle of a thriving Muslim community. The news of their encounter was transmitted around the globe, and Livingstone instantly became one of the world's first international...