Google Books aims to catalog and make searchable, scan and digitize, all the books in the world. In order to do that first they have to determine what exactly is a “book?”
We’re not going to count what library scientists call “works,” those elusive “distinct intellectual or artistic creations.” It makes sense to consider all editions of “Hamlet” separately, as we would like to distinguish between — and scan — books containing, for example, different forewords and commentaries.
One definition of a book we find helpful inside Google when handling book metadata is a “tome,” an idealized bound volume. A tome can have millions of copies (e.g. a particular edition of “Angels and Demons” by Dan Brown) or can exist in just one or two copies (such as an obscure master’s thesis languishing in a university library). This is a convenient definition to work with, but it has drawbacks. For example, we count hardcover and paperback books produced from the same text twice, but treat several pamphlets bound together by a library as a single book.
That settled, how many are there:
The answer changes every time the computation is performed, as we accumulate more data and fine-tune the algorithm. The current number is around 210 million.
Is that a final number of books in the world? Not quite. We still have to exclude non-books such as microforms (8 million), audio recordings (4.5 million), videos (2 million), maps (another 2 million), t-shirts with ISBNs (about one thousand), turkey probes (1, added to a library catalog as an April Fools joke), and other items for which we receive catalog entries.
Counting only things that are printed and bound, we arrive at about 146 million. This is our best answer today. It will change as we get more data and become more adept at interpreting what we already have.
Our handling of serials is still imperfect… At the moment we estimate that we know of 16 million bound serial and government document volumes. This number is likely to rise as our disambiguating algorithms become smarter.
After we exclude serials, we can finally count all the books in the world. There are 129,864,880 of them. At least until Sunday.
Photo via Bookshelf Porn, “A collection of all the best bookshelf photos for people who *heart* bookshelves.”