Copyright is a legal right created by the law of a country, that grants the creator of an original work exclusive rights to its use and distribution, usually for a limited time, with the intention of enabling the creator (e.g. the photographer of a photograph or the author of a book) to receive compensation for their intellectual effort.
Copyright is a form of intellectual property, applicable to any expressed representation of a creative work. It is often shared among multiple authors, each of whom holds a set of rights to use or license the work, and who are commonly referred to as rightsholders. These rights frequently include reproduction, control over derivative works, distribution, public performance, and "moral rights" such as attribution.
As far back as 1787, the United States Constitution provided for the protection of copyrights "to promote the Progress of Science and useful Arts." The contemporary intent of copyright is to promote the creation of new works by giving authors control of and profit from them. Copyrights are said to be territorial, which means that they do not extend beyond the territory of a specific state unless that state is a party to an international agreement. Today, however, this is less relevant since most countries are parties to at least one such agreement. While many aspects of national copyright laws have been standardized through international copyright agreements, copyright laws of most countries have some unique features. Typically, the duration of copyright is the whole life of the creator plus fifty to a hundred years from the creator's death, or a finite period for anonymous or corporate creations. Some jurisdictions have required formalities to establishing copyright, but most recognize copyright in any completed work, without formal registration. Generally, copyright is enforced as a civil matter, though some jurisdictions do apply criminal sanctions.
Most jurisdictions recognize copyright limitations, allowing "fair" exceptions to the creator's exclusivity of copyright, and giving users certain rights. The development of digital media and computer network technologies have prompted reinterpretation of these exceptions, introduced new difficulties in enforcing copyright, and inspired additional challenges to copyright law's philosophic basis. Simultaneously, businesses with great economic dependence upon copyright, such as those in the music business, have advocated the extension and expansion of their intellectual property rights, and sought additional legal and technological enforcement.