Google Books, a project aimed at digitizing millions of books, has been stalled due to copyright issues. The company's database contains 25 million volumes, but only a handful of engineers have access to the content. The main hurdle is unlocking the books for public viewing, requiring just one database query and flipping access control bits from off to on.

Source: https://www.theatlantic.com/technology/archive/2017/04/the-tragedy-of-google-books/523320/