Catalogers: the invisible librarians

Catalogers at work

Catalogers at work

You see their work, but when you go to the library you don’t see them. Or if you do, you can’t distinguish them from patrons like you unless you know them personally. Catalogers.

I have been haunting libraries for as long as I can remember. Especially after I got to graduate school, I became very sophisticated in my ability to use the card catalog. (That should date me.) I was ABD (all but dissertation in completing a doctorate) when I got my first job working in a library.

It was there that I learned to catalog. Until that moment, it had never occurred to me that someone actually sat down and wrote the information on those cards!

Color my face red. My mother was a professional librarian, but never worked for pay after I was born. She did a lot of volunteer library work, though, and I well remember the amount of time she sat at the dining room table with a stack of books, a stack of blank library cards, and a typewriter.

She didn’t merely type things on the cards. She had to write the description following a set of rules. The rules, the classification, and the subject headings have all changed multiple times since then, but one thing hasn’t changed: it requires intellectual work to create the records (now online) that the public sees.

Variety of library holdings

Everyone probably thinks of books first when they think of a library. There’s good reason for that. Books existed long before anything else a library might collect now. Ever since the very first lending libraries, patrons have been able to borrow books, but probably not magazines or other periodicals, and probably not whatever else the library owned for the edification of the public.

After the invention of the printing press, the distinction between a printed book and a manuscript became important. Other printed items can include not only periodicals, but music, maps, pamphlets, etc. Photographs and their precursors came along later.

The twentieth century added all kinds of non-print media: audio recordings in various formats, film in various formats, video discs, video tapes, all manner of digital media (including CD-ROMs), eBooks. Oh, and web sites.

And then there’s something called realia: physical objects like paintings, sculpture, games, a human skull. (Well, I for one would much rather dental students study a skull before they start poking around in my mouth!) I could go on, but you get the idea.

If the library has it and expects you to use it, it has to get into the catalog, which means a cataloger has to write a description of it, plus all of the other work that goes into cataloging.


Bibliographic record: what the public sees online

Library cataloging comprises two distinctly different disciplines: descriptive cataloging and subject analysis/classification. In most libraries, one cataloger performs both.

Unlike a search engine, a library catalog is a database, organized according to certain fields. That was no less true in the days of the card catalog. For example, all works have to have a title–even that skull. So sometimes the cataloger has to make up the title, too!

Other fields can include the place and date of publication, the publisher’s name, the size of the — Hmm. There also has to be a field or two to specify just what the thing is. After all, we can describe a book as being so tall and having so many pages. Try doing that with a website! An audio disc can have at least three different speeds, several different diameters, etc.

Everything in the previous paragraph is much easier to catalog than it is to make sense of all the possibilities. The cataloger picks something up and (usually) it’s pretty obvious what it is and what aspects of it require description.

There is a set of rules, now international in scope, that govern what information about a work must be described, how to describe it, and what order to put everything in.

Catalogers must follow those rules. There are at least two huge advantages to having all catalogs follow the same rules. One is that you can go to any library anywhere in the world that follows the same set of rules, search the catalogs in the same way, and discover the same things about the collection there.

Another is that libraries can share records with each other. A cataloger in one library can find a record that another cataloger has put into a huge international database called WorldCat and use it.

The record may or may not be useful without making some changes. Not everyone has to start from scratch, and if the earliest record follows only minimal standards, another cataloger can improve it and replace the old record with the better one. Then, of course, anyone in the world can use it and not everyone has to make the same improvements all over.

Controlled vocabulary

library catalog record

The same bibliographic record: what the cataloger works on

Some aspects of descriptive cataloging are reasonably straightforward. Books are measured in centimeters. Record diameters are measured in inches. It’s hard to explain why, but not hard to measure using the right unit and putting the result in the right place.

But names and subjects? Names and subjects are two major headaches. The way libraries deal with these difficulties is called controlled vocabulary.

In a library catalog, although unfortunately not in all databases, each person, corporation, or jurisdiction must be described using one and only one form. And each form of a name must refer to one and only one person, corporation, or jurisdiction.

I have written at length about how catalogers handle all these complexities so that you can find names or find subjects in the catalog. Basically, what you see in the catalog is a “bibliographic record.”

What you don’t see underneath the hood is a vast system of “authority records” that help you find what you’re looking for whether it’s Joseph Ratzinger or Pope Benedict XVI (two names for the same man).

One rule of controlled vocabulary is that when a person’s name changes, everything previously cataloged under an earlier form of the name must now be cataloged under the new one. Ratzinger wrote many books before he became Pope. The author field in all the cataloging records in the world had the name changed from Ratzinger, Joseph to Benedict XVI.

Of course, the books with Ratzinger’s name didn’t change. So the title field of every record contains a statement of responsibility that is copied directly from the item being cataloged. The name Ratzinger remains in that part of the record.

Corporations and government jurisdictions change their names from time to time, too. The same basic principles apply.

Subject analysis

Card catalog

Card catalog, and old but very sophisticated technology

It’s one thing to describe an item and something a little different to determine what it’s about. Subject analysis therefore, is a different discipline. The cataloger looks at the title, table of contents, etc. and then goes to the list of subject headings to choose the most specific heading(s) that fit the item.

There are no rules for subject analysis comparable to the rules for descriptive cataloging. And not every library uses the same system of subject analysis. Fortunately, the same concepts of controlled vocabulary govern subject headings.

Most public libraries use something called Sears subject headings. Most academic libraries use subject headings issued by the Library of Congress. Medical libraries use Medical Subject Headings issued by the National Library of Medicine.

Where Sears and Library of Congress use “Cancer,” Medical Subject Headings uses “Neoplasms.” Where Sears uses “Pigs,” Library of Congress uses “Swine.” Although it may help library users to know which list of headings they’re using, it’s not necessary.

The same authority structure that directs you from the old heading for Joseph Ratzinger to the new one for Benedict XVI directs you from a wrong subject heading to the right one.

Plus, there is no need for you to begin a search by looking for a subject any more. In the days of card catalogs, most libraries had the book(s) of subject headings out where anyone could look through them. Patrons could look for what they thought might be the subject heading, and if they were wrong, the books would tell them where to look.

You can’t look up anything by keyword in a card catalog! But that’s the best way to begin a search in an online catalog. Whenever you find one item that fits your needs, you can look for the subject headings on that record. Each subject heading is a hotline that will take you to a list of everything else the library has with that heading.


Classification is closely allied to subject analysis, but the cataloger assigns a number (which may include letters as well) to match the primary subject heading.

Again, not all libraries use the same classification scheme. Most public libraries use Dewey Decimal Classification. The Library of Congress and the National Library of Medicine also issue their own classification systems. Most academic libraries use Library of Congress Classification.

In most, but not all, libraries, the classification number determines where an item goes in the collection. It used to be called a call number back in the days when patrons had to sit in a reading room and have library staff bring books to them. Now it basically marks shelf location.

When you see the classification number in the bibliographic record, you will find the item in the same place as everything else with that or nearby number. In most libraries, something on the spine underneath the classification number will further define where the item goes, usually based on the author’s name.

After all, there may be shelf after shelf of books or other items with the same classification number. My latest book is on the history of the trombone, not one of the more crowded parts of any classification scheme to be sure, but it will serve as an illustration.

In the Library of Congress Classification, it’s ML965.G83 2010. ML965 is the classification number for trombone history. The .G83 is based on my name, and the date is the date of publication. The whole string makes up the official number and is unique.

My earlier book, also on the history of the trombone, is ML965.G84 1988. The difference between the 3 and the 4 has the effect of putting the two books on the shelf in alphabetical order by title.

In Dewey Decimal Classification, the more recent book is 788.9309, although smaller libraries can shorten it to 788.9. (The entire “780 schedule” of Dewey was completely rewritten between the two books, so the Dewey number in the cataloging record inside the earlier book is obsolete.)

Dewey does not include any particular addition to the classification. There are several accepted methods of making one, including simply the first three letters of the author’s last name. Dewey libraries can make these extensions of the classification number unique or not depending on their own policies.

To summarize then, here is what those unseen intellects have done to help you find what you want:

  • Described each item in detail so that you can look at the record and know if it fits your needs or not.
  • Formatted every name in each record so that any work associated with any one person (etc.) will be collected together no matter how many different forms of the name may exist.
  • Formatted every name in the entire catalog so that people with similar names have distinctly different headings, even if the name is as common as Jack Smith.
  • Chosen subject headings so that, at the narrowest level of specificity, everything the library has on that subject will be kept together in the catalog.
  • Chosen a classification number that keeps like materials together physically in the library to help you locate it.
  • Added an extension to the classification number to keep like materials in a particular order on the shelf.

Photo credit:
Catalogers at work Some rights reserved by sundaykofax.
Card catalog. Some rights reserved by candyschwartz.


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