How many books are there in the world?

Trillions or even more.

Do libraries take decisions to get rid of books due to lack of space or just build more space?

For eg. There are large number of scientific institutions all over the world with large numbers of scientific literature, journals, abstracts etc etc. Some dating back from 1920s. Other than antique value they hold very little scientific value. Most of the experiments have been reproduced so the data is secure. Why keep these old journals? Most of the work detail in them is practically useless now. And practically every university town has copies of all these in their libraries. Where is the antique value.

Do varsities have the courage to get rid of them or will it be considered crazy to even contemplate such an idea.

I doubt there are one trillion books in the world, let alone trillions.

Google estimates that there are 129,964,880 unique books in the world. Obviously there is a large range in the number of copies of each of those books. Best sellers may have millions of copies but the majority of books probably have a few thousand copies or less. Publishers Weekly says the average book sells 3000 copies in its lifetime. Multiplying those numbers gives about 400 billion individual books. I suspect that’s an overestimate, as Google’s number counts particular editions of the same book as separate books, and counts things that aren’t really “published” (like master’s theses which may have only one or two copies).

How many books are out of this world?

The vast majority of libraries weed books based on usage (if a book hasn’t been checked out in 5 years, 10 years, etc) it is weeded.

Research libraries usually keep books, although they often shift little used books to long-term storage.

When you start counting digital copies it gets weird, because a digital copy can be 1 or a billion depending on how many people decide they want it.

With the bible alone, there are probably a billion copies sitting around on earth. Mao’s ‘little red book’ had 800 million copies. I’m sure some have fallen apart by now.

FWIW, before the printing press there were supposedly only 30,000 books in all of Europe. Some personal libraries are larger than that now.

I don’t have a factual answer to OPs question, but a trillion total books in print might not be so outlandish (especially if you also count digital books).

Well, that’s true of physical books too. When more people want it, more books get printed. It’s just easier to “print” more copies of a digital book than of a physical book. But I don’t think the OP was asking about digital books, given his comments about space for the books.

The assumption that old scholarship can be pulped because we have newer, shinier facts applies in some fields but not others. In areas like biology initial publications, which may be descriptive lists of plants oranimals made in 1825 constitute basic, non-repeatable observational data that is essential and relevant for all manner of modern research questions.

The same holds in archaeology, where the process of discovery is very often the way that the actual resource is destroyed, anthropology, history and perhaps applies to some parts of astronomy as well.

Also many older print run journals have been replaced with either free or paywalled subscription archives. For university libraries at least that allows them to either deep-store or trash physical holdings.

In my limited exposure to the politics of how this all works, there are two potential threats to older library holdings. Only one of them is the bean counters, the other is the scientists/academics who have moved into administration from fields who think that their own model of how data and information exist applies to the world at large. Sheldon Cooper-like arrogance is not entirely a fictional trope.

The British Library has an archive in Boston Spa in yorkshire. Every year they would hold a book sale of books that hadn’t been checked out in years. I was at uni in York so I would go along and get as many books as I could carry and then reference them in essays just to annoy my professors. I was easily amused in those days!

The British Library fills 6 miles of book shelves every year with new books.

And fires! :eek:

April 29, 2986 fire at Los Angeles Public Library.

The Legacy of the Central Library Fire

Oh, and there was that fire at a certain library in Alexandria.

It does. For instance, every ancient reference we’ve found to the color of Sirius refers to it as red. With current models of stellar evolution, we can’t explain this: It certainly isn’t red now, and it’s not such an active star that it should be changing significantly in a mere few thousand years. Now, maybe those references were just meant metaphorically, and that it was “red” by virtue of being associated in some way with warfare, fire, or blood… but what if it wasn’t metaphorical? Even if it’s really bad data, it’s the only data we have, and so some theorists have tried to come up with explanations for why it might really have been red.

Senegoid, the real tragedy of that Los Angeles fire is that their entire collection on the theory and practice of time travel, the largest in the world, was lost.

And librarians. The natural enemies of students (“This job would be great if it wasn’t for the library users”) and the natural enemies of books (“This job would be great if it wasn’t for all the books”).

My set of “The Art of Cumputer Programming”, by Donald Knuth. (With it’s own Wikipedia page:, and also named as one of the top 10 sicence books of the 20th Century), was de-accessioned (I’ve always loved that word) by my universities technical library. Hard covers, in excellent condition: perhaps reference books just don’t get borrowed often enough.

And of course librarians know that patrons (oops, “clients” - management has no classical education!), just want to keep everything – which is why libraries use locked skips for some some of their de-accessioning, and why an acquaintance spent an entire afternoon smashing records when he was the most junior librarian at a city library…

You don’t need to keep (multiple copies of) everything. You do need at least one copy of everything. Off-site is OK, especially if most of that is accessible online.

(That might explain why a popular reference book would be taken off the shelves, if everybody is accessing the electronic edition, though it still seems fishy. For less popular works, it is common for them to go for decades between borrowers.)

Libraries also have to weed out books that are just old and outdated. I was a librarian at a school on the Navajo reservation once. A librarian at another school on the rez told about weeding an old book about Native Americans. The book stated that Navajo were “good Indians” (because they hadn’t really waged war against whites) while other tribes were not.

And clearly no Navajo would want to learn what Americans were writing in the early 19th century. Bring in the Firemen.

At my branch library the other day I noted 3 copies of Hidden Figures (the book) next to each other on the shelf. Multiple copies are rare for the Science section. In a couple years there probably won’t be 3 copies in the whole system. The extras will be sold at their book sales.

That’s the biggest source of waste for a regional library system. They have to buy boxes of the latest best sellers and then dump almost all of them after a bit. I don’t mind when it’s something like the latest Outlander book. But when it’s the latest political screed by an extremist nutjob and there’s a dozen copies in the new books section, that’s my tax money being wasted. (And it’s always just one side of the spectrum, as well.) Or it’s the latest book that “proves” evolution is false. And it’s filed under “Science”.

I want to amend what I wrote about needing (only) one copy. You need one copy, plus a way of getting more if and when anything happens to it. Since most books are out of print, perhaps a high-resolution digital backup? (I have at least seen books reconstructed from cheap photocopies sitting on the shelves.)

Librarians? What are current practices? Assume you are a research or national library with adequate funding.

There’s a difference between a circulation library (your average community library) and an archive library (the Library of Congress).

Circulation libraries have the mission to serve the needs of the community, but have competing constraints. First off is space - it takes tax money to build libraries or enlarge them. Ergo, there’s only so much shelf space. Second, personnel. It takes librarians and library staff to operate, and the larger the collection, the more staff. That’s tax money that competes with the rest of the city budget. Need more firemen? Guess we won’t get that extra library assistant we desperately need to help cover programming.

Additionally, there is relevance of the material. Older works may be disposed of because they aren’t being checked out and newer books are in demand. This is not a travesty - that’s the role for archive libraries. Circulation libraries serve the active needs of the community, and if books aren’t being checked out, they aren’t actively serving anyone’s needs.

Multiple copies of new popular works are useful - when the demand for a new book is a waiting list 100 people long, you don’t want just one copy and they all have to wait for it. Again, the demands of the community mean multiple copies. And yes, eventually the demand drops and those extra copies are now superfluous space users and are, therefore, ripe for being weeded.

Scientific works are somewhat different than casual reading. They have value as the prime reference or as early observations in the field, etc. Again, it depends upon the library. A civic library has much less need to hold onto scientific works. A University Library has more need to preserve access to references, but even they face challenges of space, cost, etc.

As material becomes archived and accessible online, the driver to hold onto the physical texts in multiple libraries disappears. Anyone wants to look up that reference, they have access from their office or home and don’t need to traipse to the library to find the remaining copy in the back archives.

But, as mentioned, archive libraries serve the purpose of preserving works for the future.

Melbourne, I don’t know what you mean by “locked skips”.

Also, removing the book from the school library does not make the book inaccessible to Navajo wishing to find out what Americans in the 19th Century thought. But judgmental tones in books being read by schoolchildren can affect their self-esteem and pride in their heritage.

How many books are there in the world?

At least 50. I can see that many on the shelves in my office right now.

Do you have a cite? I’ve got a mess of books (:)) on that and I’ll look into it, but I’m just wondering your source.