The copyright page.
Most of the time, no one really notices it. The majority of readers don’t have much reason to – it’s stuck in the front matter that just gets in the way of finding the Table of Contents or first chapter.
It’s useful for citing a book, whether a simple high school report or a nonfiction tome several hundred pages long. But most people don’t write nonfiction books, and I honestly doubt most of my classmates ever cited anything after their final graduation. A number of my grad school classmates would have, and several of them do teach English and Composition courses where students have to look at that page, but the others? Not likely.
In today’s world of increasing digitization of library records, it gets even less likely. Both colleges I attended had an Internet-enabled catalog that included everything needed for the minimum of MLA and other citations, and sometimes everything the more intricate MLA forms could need (hello, books with multiple authors, multiple editors, and a translator–and multiple editions). No need to look at the copyright page, just copy and paste from the official library records, then apply the right item order and formatting in the citation.
But at the same time looking at it has become less necessary, the copyright page has become generally more useful.
The practice of putting the ISBN on the copyright page seems to have started about the time ISBNs came into use. This is incredibly useful when trying to use personal library software with books that came from any of a number of booksellers who obscure the ISBN. (Yes, college bookstores that stick the USED sticker over the cover ISBN, I am thinking about you. You, and K-mart’s forced “Scan inside front cover” practices.)
The IBSN itself isn’t useful for much more than Internet searches for library software once you own a book, though. It changes with format and edition shifts, so that hardcover purchased when a book came out doesn’t have the same ISBN as the trade paperback does months later.
The real reason I adore the current copyright page practices? People finally thought to include the Library of Congress card information.
It’s been a practice for a while to include the LoC card number. I suppose this was and remains useful to actual libraries that could access that record, but the numbers start showing up before Internet access was common. For people who can’t access the Library of Congress card records, it doesn’t do all that much good.
But now? It’s usually the actual card information, which is far more than needed for simple citations.
They include the Dewey Decimal and LC numbers now.
For most people, that probably doesn’t mean much of anything, particularly since “Look in the front of a book in the bookstore, and you’ll find out where it’ll be on the shelf in the local library” isn’t something the publishers and bookstore companies are likely to shout from the rooftops.
It would have been useful for the woman who ran the library at the church I attend, though. When there was a workday in there earlier this year, we discovered the church had several copies of the same book, sometimes even the same edition, under completely different Dewey Decimal classifications. Since the books didn’t come with the number, she’d used a guide to the system to guesstimate where they ought to end up. At least one book had a copy under “Religion” and another under “Childcare”. Since the records weren’t in a computer database and the physical card catalog was nowhere near up-to-date, no one had noticed before. I’d imagine ours was not the only small library that ever happened to.
It’s useful to me in contemplating trying to document my own book collection again (I always manage to either nearly finish, or only manage to record certain books and not others), because I’ll have a way to figure out at least which of the newer books fit into subject clumps.
And it’s going to be useful to me and therefore to you once I manage to start doing book reviews here, because I can tell you where to find something in the library instead of only being able to offer an ISBN, even for nonfiction.