In this Audio clip, Randy Alcorn gives an introduction to his book The Chasm.
Did Pilgrim’s Progress Impact Your Writing of The Chasm?
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Some comparison between Pilgrim’s Progress and The Chasm is valid, but I'm sure the total sales for my book will fall woefully short! However, unlike Pilgrim’s Progress, The Chasm is not a strict allegory, in that not everything represents something else. It's more of an otherworldly retelling of the gospel story, with references back to the character's life on earth.