Copyright is a form of intellectual property. It applies to things that are expressed in words and various art forms.
Copyright is recognized worldwide, and is controlled by US federal law, the national law of other countries, and international law and treaties. Copyright violations are treated as both a criminal matter (fines, jail time) and a civil matter (law suits.)
Copyright protects:
When a rightsholder that is a person dies, the copyright passes on to their heirs. When a rightsholder that is an organization dies, the copyright is one of the assets that is disposed of. In this way, copyright is treated something like real estate.
Copyright is distinct from patents, trademarks, trade secrets, plagiarism, and moral rights to the integrity of a work.
Other forms of intellectual property:
It is important to distinguish issues of copyright infringement from issues of plagiarism. In an academic environment, we are attuned to the notion of giving credit through proper citations, and to making sure that whatever we put out is sufficiently original. This is crucial for academic integrity, but does nothing to protect against allegations of copyright infringement.
Copyright does NOT protect:
If you copy facts and ideas, or imitate art too closely, without giving credit or without putting enough of your own knowledge and creativity into your work, then you are guilty of plagiarism, but not copyright violation!
It's also important to talk about moral rights to the integrity of the work, which are part of copyright law in some other jurisdictions, but are not part of U.S. federal copyright law. In a country where copyright protects moral rights, the owner of the copyright has some say in how the content can be used, so that it can not be used in a way that would reflect poorly on the original material or its creator. For example, if a reviewer wrote a negative review of a play and the producers of the play snipped out a positive-sounding phrase and put it on their advertising materials, that could be construed as a violation of the rightsholder's moral rights. As long as it otherwise fits under Fair Use, that would be legal in the U.S., although it wouldn't be ethical. Moral rights become relevant under copyright law only if they affect the rightsholder's economic rights.
In order to be copyrighted, a work must be:
The only thing that needs to happen is that that work of original authorship gets fixed in that tangible medium of expression. It's copyrighted as soon as it's written down, drawn, recorded, whatever.
There is a way to register a copyright, and it's necessary to do that to defend a copyright in court. That will be discussed in the Your Copyright section.