Labrary Numbering Systems: Why Two?

Today at lunch we got into a discussion about the Dewey Decimal System (henceforth, DDS), used for classifying the subjects of books. Someone remebered that there is also the Library of Congress numbering system (henceforth LoCs).

I seem to remember that the DDS is used in public libraries and the LoCs is used in college and university libraries.

So: why two library subject-classification systems?

My guess is that the DDS does not scale well to collections of millions of books, such as can be found in university libraries. One of the other people guessed that the Library of Congress and its system predated John(?) Dewey, the inventor of the DDS.

Your first guess is (probably) the correct one. For a library with a few thousand books (which covers most small-town and high school libraries) a 4-5 digit numbering system is quite adequate. Also, different libraries may give the same book a different DDS number, so this system is better suited for libraries that don’t do much inter-library loaning.

When you start getting into the million-book range (city and university libraries and, of course, the LoC), and libraries that do extensive inter-library loaning, you need a system where not just book, but almost every potential book, will have it’s own unique number. For this, the LoC system, which has IIRC, somewhere between 10 and 15 digits and letters, is very well suited.

Perhaps as more libraries are connected together through the net, there may be more incentive for even the smaller libraries to convert to the LoCs so their books can be easily located by people in other libraries.

As for your second question, I would guess that the DDS is older than the LoCs, but that’s pure speculation.


I’ll take a guess.

The DDS is likely used in public libraries because it’s generally simpler. Each 100 numbers is a broad classification–the 900s are for history (including biographies), the 700s are for the arts, the 100s are for philosophy, and so on. It further subdivides, of course, but with a little practice, the general public shouldn’t have too many problems with it.

But for scholarly or academic research, something more exact is needed. IIRC, the LoC can be that way: P is literature, PG is Russian literature, and so on. (I hope these are right; it’s been a long while since I’ve used such a library.) But there can be many more starting classifications beyond the 10 that the DDS uses, which could be quite handy when dealing with huge collections.

Like I said, it’s a guess.

Only the SDMB would care to learn about the intricacies of library classification systems.

The Dewey Decimal System, first propounded by Melvil Dewey, the god of librarianship, served to divided up knowledge into 10 nice categories. Each categories would then be subdivided into groups of ten and further until you get some incredibly long and unwieldy numbers.

The Library of Congress System, LC, uses the letters of the alphabet along with numbers and breaks down information in to many more divisions.

The advantages of each are easy to spot. Smaller libraries can use Dewey and its relatively short numbers to divide a library’s collection into easy to use chunks. Religion? Go to the 200s. Mathematics? Go to the 510s.

As for LC, it is useful in that a big collection, like that found in a university, can be even more narrowly classified.
Need books on liquidity in economics. Go to HG 178. In Dewey, it would be, “start in the 330s and then look around a bit.”

Dewey has some problems dealing with newer types of information. Books on computer programming usually get classified in the 000s, which is where general reference books get classified. But you can also find UFOs and books on journalism there as well.

Religion may be the 200s, but Christianity takes up 200-289. All other religions go in the 290s.

The people who own the Dewey Decimal System (it’s propietary) make revisions every few years, but it’s a real pain to retrospectively change the call numbers of books, so some books “reside” under weird call numbers. The music section has been changed a lot throughout the years.

Also Dewey doesn’t handle works of fiction, so it all gets classified by the name of the author. In LC, everything gets a call number. Works of fiction are usually classified by the language and style of the work. This makes it a lot easier to find literary stuff. Dewey has a literature section (the 800s), but it’s reserved for plays, poems, essays and criticism.

There are additional classification systems. In particular medical libraries use a different one since they have so many books on medicine, they need their own system. Also some libraries just arrange books by their accession if they are in a closed area and have to be paged. NYPL is one example of this. You can’t go over to the 5th Avenue branch and browse.

It’s been a few years back but I was tring to order a book from B. Dalton or a similar store and felt smart because I had found the LC number. Didn’t do any good, “they” use the ISBN number. So there are actually three ways to classify books. Although the ISBN numbers may not be considered classification numbers?

ISBN stands for “International Standard Book Number” so to avoid displaying ignorance one should never say “ISBN number,” it’s as bad as saying “ATM machine.”

Bowker is a company in Chicago that publishes Books in Print, the bible of the publishing industry. Bowker assigns each publisher the beginning part of the 10-digit ISBN. The publisher then fills in the rest each time they issue a new title or new edition. I once worked with a publisher who had a range of numbers assigned by Bowker; the new titles were simply filled in, in numerical order, as they were published.

It’s not a classification system at all – just similar to accession numbers, i.e. first come, first served.

Ok, (non-practicing) librarian here.

First of all, the DDC is not a system with 4-5 digits. What you see in most public libraries is a trancation because four digits after the decimal is usually enough to provide sufficient specificity.

One thing to note about the DDC, it is a proprietary classification system. I forget who owns it now, but it is not in the public domain (libraries don’t pay to use DDC, but the people who catalog books have to pay for the source materials).

The big flaw with DDC is that it did not leave enough room for new stuff and was too focused on an agrarian United States.

The problem with LC is that it is not intuitive. Believe me, as someone how has spent hours of his life helping freshmen determine which comes first:

HC104.13 .B13 or
HC104.13 .B4

ISBN is not a classification system, it is a cataloging system. Books are just randomly assigned ISBN’s, with no regard to content (though various portions of the ISBN tell you who is the publisher and such things).

If you ever want to see the work that goes into consistent and logical classification go to your library and ask to see the LC and DDC schedules. They pre-organize knowledge to an incredible level of detail.

I sit corrected! I realized the redundancy, after posting of course. I always hear folks refer to IBM machines too!

No, I can’t see that the ISBN (International Standard Book Number) could be called a means of classification, but it provides a unique identifier (for different edition, paperback, hardback etc.) Booksellers don’t generally want to spend their time doing arcane cataloguing and classification when their primary aim is to sell the books.

Anyway, there are other clasification systems, (UDC Universal Decimal Classificaion) is only one that springs to mind) particularly in the sense of specialised fields having a system tailored to their requirements. Oh, yeah, there have been many classification systems, and isn’t amazing how they usually manage to have an extremely odd way of dealing with the book that you desperately want? (Or maybe that’s just me.)

At least computerised catalogues these days give the user a sporting chance of locating the desired material by keywords etc. As has been pointed out, libraries cannot always (or even usually) have the entire collection adhere to one version of, for instance, Dewey, as retrospective cat. & class. is too expensive in terms of staff time.

I should stop this somewhat embittered rant. Would it amuse anyone to know that in the U.K. in the 1980s, at least one of the loonier tabloid “newspapers” got all uptight about the fact that public libraries all over the country (using Dewey) were being utterly treacherous in classifying the Malvinas/Falkland Islands under Argentina?

The Library of Congress classification originated when Thomas Jefferson sold most of his book collection to LC to replace the library in the Capitol burned by the British in 1814 (Congress needed books; Jefferson was badly in need of cash, as Monticello was never a profitable agricultural enterprise). Jefferson had already classified his collection according to the major divisions of the fields of knowledge. For the rest of the 19th century, LC classification was based on modifications of Jefferson’s original scheme.

At the beginning of the 20th century the LC classification scheme underwent a major overhaul. They began using the letters from A to Z for the major subject classes (O, W, X, and Y are omitted, so there are twenty-two major classes). This is the scheme that, greatly elaborated, is still in use. Although perhaps inspired by the general outline of the Jeffersonian classification, the new LC scheme doesn’t resemble the older one much. So in a sense its roots go back to the early 19th century, but in fact the scheme now used is only about 100 years old, making it younger than Dewey’s, which started in the 1880s.

Keep in mind that there is the LC Classification number of a book (e.g., PE 1100 J35) and the LC Catalog Number, which is usually in the form of XX-XXXXXX. The first two digits being the year of publication and the last set an accession number.

You can use this info to win bar bets at librarian hangout bars.

Don’t laugh. I’ve known quite a few alcoholic librarians.

> librarian hangout bars

There’s a niche business if I’ve ever heard of one!

Then we probably shouldn’t discuss the ultra-niche that is librarian porn.

Yes we should. My nephew is a research librarian and I need something to hold over his head!

TampaFlyer, where’s the problem here? - surely it’s clear that classifcation systems are designed to drive one to drink.

In fact, I remember, at library college, having a plan to run a bar which would have to have every drink that could posssibly be wanted, and, for ease of retrieval, would have them all really carefully classified under a wonderful specialised system yet to be devised and perfected. I think we moved on to quality testing of the drinks, and neglected the grand plan for some reason.

Celyn (recovering librarian and recovering philosopher)

Huh! GaryM and Obfusciatrist(sp?) beat me to the draw. Still, the librarian porn game could be fun. “Debbie does Dewey”, “Librarians in Congress”. And there ought to be a film named “Acidhead Virgins” tho’ that’s too boring to explain.

And the staff of the National Library of (name withheld) once got thrown out of a bar and asked not to come back again after getting drunk and obnoxious at the Christmas party.

I would argue that the LC system is intuitive. It seems pretty straightforward to me. Here is the handout I give to students I am training: (click me).

The issue that hangs people up is that the cutters that come after the Specific Subject are decimal. But oddly, I find that a lot of our patrons don’t understand why they can’t find a TK 40 in the middle of the TK 4000’s.

The Cutter system (which is also proprietary I believe) is a whole different animal from either DDC or LC.

As librarians, we must keep certain parts of our collections inaccessible to some people so we can remain employed. It’s all rather insidious.