Most people in the English speaking world have heard of Shangri-La, but fewer know of Lost Horizon, the James Hilton novel that introduced the idea of the mystical utopia. Many even think that the city is an actual ancient Tibetan legend and not a 1930's English fabrication! In my opinion, this illustrates how influential the novel and its film adaptation were in their time. All that is to say, what are some other books whose elements have become more widely known than the books themselves?