Hi welcome to my ted talk let's get right into it
Our topic for today is….. drumroll please………..

Now don't get me wrong. Books are great! I read many books[citation needed]! I just think… we can do better than (bound, printed, western-style) books for something as grand, mystical, and eternal as the ol' Wanderers' Library. Obligatory I am speaking about my personal headcanon - feel free to imagine the library however you like
Why do I say such heretical words? Because books don't last. Not well, at least. We live in the beautiful age of the printing press where a ruined book can be easily replaced by going to the local Barnes n' Noble. But while the bound page is excellent for densely storing lots of information at once, it has a tendency to, well, wither to dust and blow away given enough time.
True story: my grandma has a copy of a (nearly lost media) autobiography from 1922. It's an incredible work of art, with great narrative style and hand-drawn illustrations…. that is almost completely inaccessible because it disintegrates at the slightest touch. I broke the spine by bumping it one time. If I were to go to a restorationist now, the only hope of salvaging it's pages would probably be to dissect it, scan every withered spread and then view it on my computer's photo app.

Now, there's an incredible amount of variation in each incarnation of the Wanderers' Library. It may be malevolent, it may be sapient, it may be infinite or fractal or what-have-you, but an overwhelming majority of presentations make the 'books,' well, books. Exactly the way we happen to make them. A big part of this is probably the familiarity and coziness of a local bookstore, of course. But I dare say it runs into some hypothetical flaws when we expand the scope to an entire, multiversal Library filled entirely with them.
If the Library is older than half a century, many of their tomes would be too frail to touch without gloves. Older than a few centuries, most would be unrecognizable and/or dust piles. Then take into account that these are meant to be checked out and read by a variety of people. What happens when someone dog-ears a page and the corner rips off? Or spills their juice? Paper can be so fragile that I've torn pages out by accident simply by flipping them too hard.
Imagine the logistical nightmare replacing old books would be. How many Pages would it take to comb through every shelf for books that are bent or spoilt? Would they have to print a new copy every time? That'd take a lot of industrial machinery and ink jams. It'd be like printing out every page of the latest revision of Wikipedia, if you get that reference— the WL would be stuck in an endless cycle of wheeling out new books and replacing unreadable ones to the point that little else would happen.
Of course, all of this could be solved by inexplicable magic. Maybe the books are super-duper immortal, indestructible things that never age or yellow or get weird sticky gunk between the pages. Putting aside that that'd negate plotlines like the Searing or Bookworms, there are other critiques to be had of universal books-as-default beyond logistics. What about cultures that don't traditionally have pagebound novels, for example? Many people have debated how books being held as the superior form of information capture can be a kind of cultural imperialism when dealing with groups that perhaps didn't write, or encoded knowledge in other mediums.
And as my final point:: I just think the Library would be even weirder (in a cool way) and cooler (in a weird way) if it didn't conform to our expectations of how a modern library looks and behaves.
So. Like. If not books, how else would the Library work?
Here's where my brain starts shutting down from sleep deprivation! But I think there are a crazy amount of possibilities for dense information storage that are both A. more indestructible than paper and/or B. cool as hell. I encourage y'all to come up with our own, ofc! or don't! you can do whatever you want forever :D
- MASSIVE ENGRAVED STONE COLUMNS. There's a reason the Rosetta Stone aged well while contemporary papyrus fared worse. Stone is notorious for lasting an extremely long time through the elements. I can envision a dense, glyphic script (perhaps akin to Braille) that is carved into the sides of titanic stone pillars. Many books can coexist on a single column, given enough height and a good ladder, and and it'd also be more accessible to the denizens of the multiverse who don't see the way able-bodied humans do. Maybe the columns hold up something big and important too!!!
- SCANNED ONTO ROLLS OF FILM. The original source material is left in it's home universe, but every page is meticulously transferred onto a durable film. I actually read somewhere that a particular type of film is the strongest for long-term information storage, but I can't find that factoid anymore. Instead of storing physical books, each shelf is actually a drawer of neatly packaged film cartridges that are loaded into a projector and flipped through, page-by-page.
- WEIRDER SHIT. Maybe each word is laser engraved into quartz crystals that must be held at a certain angle to project the words into their shadow. Maybe each book is a foamy layer in a multilayered liquid that must be coaxed to the surface. Maybe it's just a cloud-based Super-Wikipedia (but that's kinda boring). There's a lotta possibilities once you factor in magic and alternate physics into the mix!!!
I'm about to conk out now, so my parting words shall be….