His mind crowded with vivid images of Africa, Graham Greene set off in 1935 to discover Liberia, a remote and unfamiliar republic founded for released slaves. Now with a new introduction by Paul Theroux, "Journey Without Maps" is the spellbinding record of Greenes journey. Crossing the red-clay terrain from Sierra Leone to the coast of Grand Bassa with a chain of porters, he came to know one of the few areas of Africa untouched by colonization. Western...