Hot Tub High School for the DVD section. I hear Chloe Decker is gonna be a BIG star.
How about Don Quixote, the Pierre Menard version?
Dreams of a Prodigal Child by John Dorman, mentioned in The Gift of Asher Lev. The only book published by the author, who continually writes, so maybe you could find and published the others.
If you’re into the Necronomicon, I recommend:
From the Supernatural universe:
John Winchester’s journal
Samuel Colt’s journal
The Winchester Gospel
Book of Shadows
Book of Spells
Book of Fenris
The Black Grimoire
The Book of the Damned
The Demon Tablet
The Angel Tablet
The Leviathan Tablet
The Ledger of the Thules
On the Inner Workings of Angels by James Haggerty
Everything in the Men of Letters bunker
God: An Autobiography by God
From the Buffyverse:
The Slayer Handbook
A Treatise on the Mythology and Methodology of the Vampire Slayer
Various and sundry Watchers’ diaries
The Pergamum Codex
The Scrolls of Aberjian
The Books of Ascension
The Merenshtadt Text
Darkest Magick
The Necronomicon des Mortes
The Nyazian Scrolls
The Black Chronicles
The Magdalene Grimoire
The Gutenberg Demonography
The Brekenkrieg Grimoire
The Tome of Moloch
Bynum’s History of Witchcraft
Bristow’s Demon Index
Exploring Demon Dimensions
Dreadhost’s Compendium of Immortal Leeches
Hochstadter’s Treatise on Fractal Geometry in 12-dimensional Space
Hume’s Paranormal Encyclopedia
The Xiochimayan Codex
The Book of Kelsor
Everything in Giles’ library
That oughta keep ya busy for a while… 
This should take up most of a shelf:
Ten Nights in Ten Haunted Houses
Ten Nights in Ten Haunted Graveyards
Ten Nights in Ten Haunted Castles
by Mike Enslin
From Phineas and Ferb: The Movie-- the pamphlet, “So You’ve Discovered Your Pet Is a Secret Agent”.
Ethel the Aardvark Goes Quantity Surveying
Thirty Days in the Samarkand Desert with the Duchess of Kent" by A. E. J. Eliott, O.B.E.
The Amazing Adventures of Captain Gladys Stoutpamphlet and her Intrepid Spaniel Stig Amongst the Giant Pygmies of Beckles, Volume 8
Do you think you could possibly get a hold of the following for me?
If on a winter’s night a traveller by Italo Calvino
Outside the town of Malbork by Tazio Bazakbal
Leaning from the steep slope by Ukko Ahti
Without fear of wind or vertigo by Ukko Ahti
Looks down in the gathering shadow by Bertrand Vandervelde
In a network of lines that enlace by Silas Flannery
In a network of lines that intersect by Silas Flannery
On the carpet of leaves illuminated by the moon by Takakumi Ikoka
Around an empty grave by Calixto Bandera
*What story down there awaits its end? * by Anatoly Anatolin
I started reading them once but just never seemed to be able to finish them…
Bumped.
Cardinal John Brannox (John Malkovich) in the HBO series The New Pope wrote a bestselling spiritual book, The Third Way, before his election as Pope John Paul III.
From The Good Place, Shakespeare’s The Tempest 2: Here We Blow Again
The chapter about Uqbar that’s in some copies of the Anglo-American Cyclopaedia
The Book of Sand is endless hours of fun for all ages! [ETA I see I already mentioned it. Never mind; get another copy.]
Also Achmed-the-I-Just-Get-These-Headaches’s Book of Humorous Cat Stories
Can I add a fictional work that I entirely made up? If so, I would nominate Rabelais’s recently rediscovered lost novel Pantagruel and the Antichrist.
Synopsis: Pantagruel the Giant receives an urgent summons from the Pope, and (after some delay and sidetracking) arrives in Rome. The Pope explains that a renegade prince has, by abandoning every principle of Christian society, created an earthly paradise in his realm, setting a dangerous example for the rest of Christendom. The Pope urges Pantagruel to stop the renegade. Pantagruel agrees to do this even though he ends up finding much about the prince’s experiment to admire, but concludes “men would never turn to God if they were happy in their sin”. Pantagruel’s two chief allies in this project are a cult of heretics, who moved to the prince’s realm to obtain religious freedom only to be disappointed that they weren’t permitted to impose their heresy on everyone else; and the jews, who rued the loss of their monopoly on moneylending.
S. M. Stirling’s book Conquistador mentions some books written about the history of the world on the other side of the Gate.
The Rise and Fall of the Alexandrian Empire
The Post-Alexandrian World
Folk Migrations in Early Historic East Asia
The Selang-Arsi Kingdoms
The Eastern Iranians
Post-Celtic Europe
The book-within-a-short-story of the same title as George R.R. Martin’s 1979 “The Way of Cross and Dragon,” a heretical Gospel of Judas Iscariot in a fractured, distant-future Catholic Church.
The novel The Abortion: An Historical Romance 1966 by Richard Brautigan concerns a “librarian of a very unusual California library which accepts books in any form and from anyone who wishes to drop one off at the library—children submit tales told in crayon about their toys; teenagers tell tales of angst and old people drop by with their memoirs—described as “the unwanted, the lyrical and haunted volumes of American writing” in the novel.”
It’s been awhile so the only book I remember from it was a book about leather fetishes, constructed itself out of leather. But I’m sure there were other notable examples.
Interestingly, in honor of the novel, a library in Burlington (since moved) started it’s own collection of unpublished works.
The Reluctant Messiah by Richard Bach and Enemy Mine by Barry Longyear both have spiritually themed quotes from books which only exist in those stories (I think The Handbook, and the Talmud, respectively). Though the latter got a few more passages and excerpts in the companion, The Enemy Papers.
The novelization of the various Robotech series has a quote from a different in universe work at the beginning of each chapter, which I suppose makes it like 5% epistolary.
Isaac Asimov quoted from the voluminous, magisterial *Encyclopedia Galactica *at the beginning of many of his Foundation stories.
The young Southern novelist Tom Yates, who becomes a speechwriter for the President and Mrs. Underwood in the Netflix political thriller series House of Cards, had earlier written Scorpio and God’s Cauldron.
SInce this has been bumped, I hope everyone knows you can take any book (or sheaf of hand-written, or even blank pages) to an old school book-binder and get a nice cloth or leather cover… with any title you want embossed on the cover and/or spine.
I’ve done it. The cover was falling off my Bible and since I was leading a Bible Study at a camp, I figured it’d be cool to be teaching from my very own Necronomicon (I realized later that I should’ve had “Abdul Alhazred” embossed underneath as the author). I also figured that anyone who’d be offended wouldn’t have read any Lovecraft anyhow, so I was safe…