Shadow libraries are online databases of readily available content that is normally obscured or otherwise not readily accessible. Such databases may be inaccessible for a number of reasons, including the use of paywalls, copyright controls, or other barriers to accessibility placed upon the content by its original owners. Shadow libraries usually consist of textual information but may also include other digital media, including software, music, or films. Shadow libraries are almost ubiquitously examples of large-scale copyright infringement.