The Pilgrim's Progress

A man named Christian flees his doomed city carrying an unbearable weight on his back, and sets out on a road lined with temptation, despair, and monsters both literal and moral, all the way to the Celestial City. Written by Bunyan during a prison sentence for unlicensed preaching, this allegory of the Christian life became one of the most published books in the English language — an adventure story and a spiritual map at once, still gripping readers who've never opened a sermon.