By the time he was twenty-two, Dan Eldon had led a relief mission across Africa; worked as a graphic designer in New York; studied (intermittently) at four colleges; traveled through Europe, Africa, Japan, and the US; founded a charity for Mozambiquan refugees; directed a film; written a book; started up his own photography business; and become a photojournalist for Reuters news agency, covering the famine and civil war in Somalia. There, in 1993,...