Undoubtedly, John Bunyan's The Pilgrim's Progress is considered one of the most influential books of all time. For many, it is second only to the Holy Bible and has been enjoyed by generations for more than 340 years. This whimsical allegory follows the adventures of a man named Christian who, after discovering a book and, subsequently, having a great burden grow on his back, journeys beyond the forbidden borders of his home in search of the Celestial City and its King.