The Internet Archive is a a 501(c)(3) non-profit organization whose goal is to provide a free Internet library. This means offering permanent access to historic collections that exist in digital format for researchers and the general public. They acquire a majority of their content with the Archive-It harvesting service using a Web crawler that collects content from the surface web. The content is maintained and served through an open access digital repository called the Wayback Machine. Internet Archive also offers book digitization services.