From an Open Library Blog Post:
A web page for every book… This is the mission of Open Library: a free, inclusive, online digital library catalog which helps readers find information about any book ever published.
Millions of books in Open Library’s catalog have been made available to preview, read, or borrow using the Internet Archive’s controlled digital lending library. However, the catalog also features tens of millions of books which are yet to have previews and instead serve as resources that help patrons learn more about books, share lists of books they love, keep track of what they’re reading, and locate copies from bookstores and local libraries.
Thousands of new books are added into Open Library’s catalog every day. Like Wikipedia, thousands of edits are contributed by community librarians and volunteers across the globe. Open Library is a community effort and any patron who registers online for a free Internet Archive library card may participate.
Since its inception in 2006, a core tenant of Open Library’s service has been the notion of one web page for every book.