Name the longest running bestselling fiction novel.
Don Quixote at 500 million + copies sold.
The bible holds the all time record for sales, but it doesn't qualify as a novel because it is too convoluted, confusing, and lacks a real plot that can be followed without considerable juggling. It certainly is the record holder for sales in poorly written books.
The Lord of The Rings - but I don't know if it ever made the bestseller's list long enough to be counted. I heard that it wasn't popular when first published.
Harry Potter could be too "young" a publication to be longest running. (And I've not read any of it.)
The Bible is too obvious an answer for it to be almost a "distractor" for this trivia question.
I vote for To Kill a Mockingbird. But I don't know.
Bible
Correct, the bible is the longest running work of fiction in history.