OCLC, the library cooperative, compiled this list based on numbers of copies of timeless works held in libraries around the world and found in WorldCat. It features some of the greatest works ever written -- all of which can be checked out from the Sonoma County Library.

From the OLCC Next blog:

"The research was based on holdings information in WorldCat, which lets you search the collections of thousands of libraries around the world. The hard part of the research wasn't counting the libraries that had a copy...it was "clustering" lots of variations, editions, and translations of books. That way, a 1964 French translation of Pride and Prejudice counts the same as an English version from 2006. The important part isn't the specific edition or version--it's the fact that this is a novel that thousands of libraries have decided to keep in their collections."