Let's face it, "Lord of the Rings" is a fantastic story, in the truest meaning of the adjective.
Well over half a million words.
The Old Testament is about the same, the New Testament around 180,000 words.
A personal favourite, John Steinbeck's "The Grapes of Wrath" is around 20k shorter.
He appears again with "Of Mice and Men" with around 28,500.
We come down to Hemingway's "The Old Man and The Sea" with a mere 27,000 or so.
All of these convey great stories, great ideas, great messages.
But surely the ultimate distillation has to be the 100 word Drabble!