" The Pilgrim’s Progress is a classic of classics. If we exclude sacred texts (the Bible, the Koran, etc.), liturgical texts (Book of Common Prayer), and political books that Chairman Mao might take a dim view of your family not owning, The Pilgrim’s Progress is arguably the best-selling book of all time." -From Dougla Canon Press resource: https://canonpress.com/products/worldview-guide-for-pilgrims-progress