While I was working at the MIA, I was drawn to cataloguing, mostly because I liked finding where a book would fit within a classification scheme. I really liked the idea that there was a place for every book, and the challenge of making a call number that would put it in the appropriate place on the shelf (this is harder than it seems!). Luckily for me, the MIA used the Library of Congress Classification scheme– an amazingly elegant system for classifying and organizing all of mankind’s accumulated knowledge. Here’s what it looks like:
This outlines the different subjects that works can be classified as, (i.e. Religion, History, Art, Science, etc.) and the various subdivisions within each field. Each broad subject is given a letter from A-Z, and more specific subjects are given 2 letters. For example, Art is ‘N’, but within art, you will find sculpture (NB), drawing (NC), painting (ND), and so on.
It gets even more complex with the addition of numbers 1-9999, which go into further detail about the content of a work. Generally, the lower the number, the broader the subject matter. So ND25 will be a general book about painting, whereas ND3416 will be about illuminated manuscripts.
You can see this in a bit more detail here: http://www.loc.gov/catdir/cpso/lcco/
(The entire classification system in all it’s detail is contained in over 20 volumes, but fortunately the Library of Congress makes it available online with a subscription.)
So this will give you the first part of a call number. The second part is called a cutter, and it’s usually derived from the author’s last name. There is a table for making these numbers:
After that, finally, you have the publication date. So altogether you have a call number that is completely unique for every book, and it will look something like this:
This tells me that the book is from the MIA, it can be found in the reading room, it’s about general art (N) from the Islamic world (6260), it’s author’s last name begins with H, and it was published in 2009.
LC classification is great for big libraries, or libraries with really specialized collections. Mostly you will find Dewey Decimal system being used in public libraries where the books are more generalized. (I’ve learned recently that I really don’t like Dewey…but that will be the subject of my next post).
Now go to your nearest university library and test out your new knowledge of LC call numbers!