Sadly, it would seem, John Bunyan's The Pilgrim's Progress is one such book. I intend to remedy that post haste.
Just yesterday, I received Crossway Book's new version of this text, "lightly edited, and updated to current language" by C.J. Lovik.
The text also includes 30 new, full color illustrations to help paint Christian's travels in our minds.
Evidently, other than the Bible, The Pilgrim's Progress is the most published book in the English language.
I am greatly looking forward to this allegorical text.