The rules governing copyrightable work created by two or more authors vary from country to country, although they tend to be similar. In the United States, work created by two or more authors
Along with trademarks and patents, copyrights are one of the basic forms of intellectual property which exist under American, European, and international law. A copyright is a legal monopoly on the right to reproduce, sell or distribute, and perform works, which is automatically granted to the creators of the work but can be assigned by them (i.e. sold or licensed) to other parties. Copyright has existed in American legislation since 1790, and in international law since the signing of the Berne Convention in 1886. In American law, copyright is granted only to works produced by individuals and, by extension, corporations; works of the government are automatically released into the public domain, meaning they can be reproduced and distributed at will. There are five components of the copyright: the right to copy it, to produce derivative works (i.e. based on the original, like a film adaptation of a book), to distribute and sell the copies, and to publicly display or perform the work (in the case of art, movies, plays, etc.).
Copyright as such was initially designed with works produced by single authors in mind, but obviously it also applies to work created by multiple authors, meaning two or more authors. In this case, the U.S. Copyright Office applies American copyright law by respecting each author’s copyrights. This means that each of the creators has the right to decide to copy, distribute, or perform the work, with the proviso that any profits from doing so have to be split equitably with their fellow authors. Of course, the authors can choose to draw up contracts specifying an alternative process – for example, specifying a different sharing system for the profits, or assigning decisions about reproduction and sale of the work to just one of the authors.
Copyright always comes with an expiration date, after which the work is said to pass into the public domain – meaning that there are no further legal rights enjoyed exclusively by the author or authors. In the case of personal copyright, American law specifies that copyrights expire 70 years after the death of the author, during which time the rights can be inherited by his legal heirs or assigned as specified by his estate. This is where the most important distinction of joint copyright, from the perspective of end readers and audience members, occurs. A work created by two or more authors is considered copyrighted until 70 years after the death of the last surviving author, regardless of how long it has been since the first or other authors passed away.