The works that Chaucer refers to in his retraction to The Canterbury Tales but that no longer exist.
Coleridge’s original version of Kublai Khan-- the one he had worked out in his head, but forgot because he was interrupted right before he started writing.
Byron and Shelley’s horror stories from the contest that spawned Mary Shelley’s Frankenstein and Dr. Polidori’s “The Vampire.”
“The Giant Rat of Sumatra,” the Sherlock Holmes story the world isn’t ready to see.
And, of course, the notorious sexually-explicit cut of Disney’s Snow White.
The complete poems of Sappho
It wasn’t just a rumour. Hemingway says in A Moveable Feast "It was necessary to write longer stories now as you would train for a longer race. When I had written a novel before, the one that had been lost in the bag stolen at the Gare de Lyon, I still had the lyric facility of boyhood that was as perishable and deceptive as youth was. " The Bag contained all his unpublished manuscripts at the time.
Three of Luther’s 95 Theses broadside still do exist - I saw one! Very cool. It was at New York’s Grolier Club, a fancy book collector’s group. They were sponsoring a show of the Bodmer collection - a European fellow with an amazing collection. He died some time ago, but provided so that the collection could be held in a museum.
In addition to the Luther broadside, he has amazing stuff like first editions of Shakespeare, Dante, Cervantes, Mozart and Beethoven. He has a Leibniz’ copy of Newton’s works with notes scribbled in the margin!! Viewing highspots of that collection was amazing.
Not exactly a work of literature, but I’d like to know what Jesus wrote in the sand in John chapter 8.
The version of “Catcher in the Rye” that everyone raves about.
The first written copy of Gilgamesh.
The Greek epic poems which predate Homer.
Pagan Germanic epic poetry.
Robert A. Heinlein’s never-written prequel to Revolt in 2100.
Oh boy oh boy oh boy…
I’ve always wanted total cataloged access to the secret archives of the Vatican. Many of the things that all of you have asked for could very well be contained in there, plus things that none of us even know exist. It’s a priceless treasure trove of ancient religious works and political information.
Not literature per se but…
The Lost score to Gilbert & Sullivan’s first collaboration: Thespis.
The lost writings of explorer, swordsman and all-around he-man Richard Burton (no, the other one) supposedly burned by his wife as too salacious and scandulous.
The third and final Dangerous Visions collection. That’ll never see the light of day.
I am not all that religious, but I’d love to read any of the books that were left out of the New Testament. For example, the Book of Timothy, where supposedly Jesus, as a young boy, turns wooden toys into real birds and they fly away, and so on. Mary Magdalene was supposedly well represented in some of these early books which were left out of the official version. [Sort of an old example of out-takes, where the original version has more life and surprise in it than the watered-down studio take.]
Couldn’t find a Gospel of Timothy, but what you described sounds like an Infancy Gospel of Thomas, for what it’s worth.
The first draft of Seven Pillars of Wisdom. I’d love to see what Lawrence had to say before he’d had enough time to think about it.
The complete Satyricon by Petronius
Pliny the Elder was Pliny the Younger’s uncle, I believe…and his encyclopedic work has mostly survived; you can find a Latin/English edition of it in the Loeb series…
That said, I would be very happy to have the lost books of Tacitus’ Annals…
Claudius’s History of the Etruscans, which supposedly had extensive language notes, as well.
“For a good time, call…”
From the Roman biographer Suetonius: Historians and philosophers.
Makes me wonder what great thinkers of the past we lost…