view: Books in the public domain are available for "full view" and can be downloaded for free. In-print books acquired through the Partner Program are also available for full view if the publisher has given permission, although this is rare. Preview: For in-print books where permission has been granted, the number of viewable pages is limited to a "preview" set by a variety of access restrictions and security measures, some based on user-tracking. Usually, the publisher can set the percentage of the book available for preview. Users are restricted from copying, downloading or printing book previews. A watermark reading "Copyrighted material" appears at the bottom of pages. All books acquired through the Partner Program are available for preview. Snippet view: A "snippet view" – two to three lines of text surrounding the queried search term – is displayed in cases where Google does not have permission of the copyright owner to display a preview. This could be because Google cannot identify the owner or the owner declined permission. If a search term appears many times in a book, Google displays no more than three snippets, thus preventing the user from viewing too much of the book. Also, Google does not display any snippets for certain reference books, such as dictionaries, where the display of even snippets can harm the market for the work. Google maintains that no permission is required under copyright law to display the snippet view. No preview: Google also displays search results for books that have not been digitized. As these books have not been scanned, their text is not searchable and only the metadata such as the title, author, publisher, number of pages, ISBN, subject and copyright information, and in some cases, a table of contents and book summary is available. In effect, this is similar to an online library card catalog. In response to criticism from groups such as the American Association of Publishers and the Authors Guild, Google announced an opt-out policy in August 2005, through which copyright owners could provide a list of titles that they do not want scanned, and the request would be respected. The company also stated that it would not scan any in-copyright books between August and 1 November 2005, to provide the owners with the opportunity to decide which books to exclude from the Project. Thus, copyright owners have three choices with respect to any work: It can