What Have We Been Eating for Breakfast?

People who use libraries often will at some point in their lives remark that the place where they found a certain book was odd. Why are most of an author's books in 900, but this one is in 200? Why are most of this author's books in Fiction, but this one is in 300? And more tantalizingly, why is our copy of a book in 900 while another library has the same book in 100?

It's called cataloging -- that's the science, the art, the practice -- whatever you want to call it, of assigning Dewey Decimal System numbers to books. The numbers mean subjects. 200's are religion. 900's are history. So if you have a book about the history of religion, where does it go? Is it more religion or history?

There is an old saying about cataloging, that the number assigned to a book depends largely on what the cataloger had for breakfast. It' not really that bad. We try to use common sense, we read what the books are about, we go by the precedent of what other libraries are doing -- and still sometimes we end up with wildly different numbers on items.

Because the Dewey system itself changes over time, the problem is exacerbated in older books. A hundred years ago, there wasn't much work being done in genetics. There was one number that handled evolution, human evolution, genetics, and more. Now, these subjects all have different numbers and, biggest surprise of all, the number that used to handle them has simply been discontinued. Of course when this happens, no library has the time or resources to go and pull all of those old books off the shelves and renumber them, so books on the same subject can be found in 576, 551, and elsewhere.

This all comes up because recently I looked up one of my favorite books, certainly my favorite book my Mark Twain, Roughing It. For anyone who hasn't read it, this is his memoir of a trip through the American West. Part travelogue, part history, part satire, all hilarious, this is one of those books that defy classification. And sure enough, when I looked at our catalog (which lists the holdings of nine different libraries), I found five copies of the book, with 5 different call numbers. They were:

917.8 -- The number I would give it, this designates the book Description and Travel in the American West
818 -- This designates the book miscellaneous literary works in English. An incorrect number, though I understand the thinking that put it there
B TWAIN -- Making it a biography. It is a memoir, so maybe it could go here . . .
817 -- American Wit and Humor, which it certainly is, but it doesn't get at the essence of what the book is about. To a degree, everything Twain wrote could go here.
F TWAIN -- Which makes it fiction, which it is not. But this is a mistake libraries sometimes make. Much of an author's work is fiction, they just assume.

Anyway, five copies of the same book, five different breakfasts. Next time you're in the library, and get to wondering why a book is where it is, ask somebody. You may be surprised by the answer -- or by the inability of anyone to explain.