Cat. & Reference: My library, by the numbers
For fun, I decided to go through my books on LibraryThing and figure out the percentage that belongs to each of the top 10 classes of the Dewey Decimal System. (Why, what do you do for fun?) I know that Dewey's system isn't perfect, but it's a place to start, and I thought the breakdown was interesting.
Here are the classes, starting with the highest percentages (and with an explanation of what subjects belong in each class):
800s = 43%
The 800s comprise "literature," so it's no surprise that this is the largest class, since I do like reading fiction. (Incidentally, most public libraries eschew Dewey's fiction classification in favor of genre breakdowns such as "general fiction," "mystery," "sci-fi," and "romance," leaving the 800s otherwise sparsely populated with texts on rhetoric or encyclopedias of literature. However, the 800s are technically where all fiction belongs, under Dewey's system.)
700s = 18%
The 700s comprise "arts and recreation." I was actually a bit surprised that this category was the second largest category, since I don't consider myself a particularly artsy. However, books on knitting, music, bookbinding, graphic design and typography all fall into this category (not to mention my lone weightlifting book), so apparently it adds up to a significant chunk.
400s = 8%
The 400s comprise "languages," so it doesn't surprise me that this is a big chunk. I'd actually have thought that it would be a larger chunk, but a lot of my foreign language literature is classed in the 800s, even though I shelve it with my foreign language dictionaries in my home library. It's also worth noting that my LibraryThing account includes not just all the books I currently own, but also all the books I recall ever reading. I'm more likely to buy reference books and but borrow fiction, so my LT account contains a higher percentage of fiction than my home library does.
300s = 6%
The 300s comprise the social sciences (with the exception of psychology, which goes in the 100s and history and geography, which get their own class). I've got a little bit of everything in this class, including books on economics, business, and books about people who fall into specific social classes (women, the working poor, centenarians, multiracial people, and the deaf). You'll find folklore and mythology at the tail end of the 300s, including the two books I own from Time-Life's "Enchanted World" series. (I'd love to own the other 19 books in the series.)
500s = 5%
The 500s are science. This includes my physics books, as well as books I've read about mathematics, astronomy, and natural history.
600s = 5%
The 600s are officially called "technology," which works out to be applied science, more or less. This class includes medicine, engineering, cooking, and also some books on graphic design. (I'm not sure exactly why my typography / bookbinding books are falling into two different general classes — perhaps it's the difference between an art and a craft, which is more like an "applied art"? At any rate, this illustrates an ongoing problem that catalogers face: Some books fit neatly into just one place in a classification system, but some books could easly be classed in two, three, or even four different places. Part of being a good cataloger is being able to use good judgment in such situations to determine where a book should go.
000s = 4%
This class includes "computer science, information, and general works." This class, as Dewey originally envisioned it, was supposed to comprise just general reference materials. However Dewey wasn't prescient enough to leave enough room in the 600s for computer science, so it had to be shunted over here when the field became large enough. Even so, most computer science books have ridiculously long Dewey numbers, because they've been wedged into a corner of the classification system that was never intended to hold them. (This is a common problem with classification systems: No matter how well you describe the world you know, there's always something new coming around the corner which will wreack havoc with your tidy little system.)
200s = 4%
For a person of faith, I don't have a ton of books on religion. I've never really been into Mormon history, though (I find it depressing), nor do I have any great interest in Mormon nonfiction bestsellers. I do have quite a bit of religious music books, but those are all classed in 700s with other types of music.
900s = 4%
History has always been my worst subject. I'm both bad at it (it makes no sense to me) and relatively uninterested in it, so opinion of the subject is basically that it's a nasty hard thing that I occasionally have to suffer through. I do better with learning history through biographies, though, because the story of someone's life seems to give me a needed logical thread by which to make sense of everything else.
In Dewey's original system, all biography was classed in the 920s. Since then, biographies have been reclassed to the subject area for which the person is famous. E.g., physicists' biographies are classed with physics, artists' biographies are classed with their artistic specialty, economists' biographies are classed with economics, etc. Only books which are about biography, generally, and biographies of political figures are still classed in the 900s. So I've read a lot more biographies than are represented here, but they're scattered throughout the rest of my library.
100s = 3%
The last and smallest class is the 100s, which comprise "philosophy and psychology." I've got a couple of interesting books in here, such as a book on the history of IQ testing (good, but sad), and books by Descartes and Pascal that I bought for one of my French literature classes. While I like books which are philosophical in nature, I don't have a lot of use for straight philosophy.