Copyrights are generally enforced by the owner in a civil law court, but there are also criminal infringement statutes.
In general, the owner of a physical copy of a copyrighted work (book, CD, etc.,) can do what he pleases with the copy, even without owning the copyright, so long as he does not produce additional copies or modified works; but there are exceptions: public performances (which are considered a form of copy) or electronic copy. In the US this is known as the First Sale Doctrine, and was established in the US court system to clarify the legality of reselling books in used book stores.
Many European countries (and other countries as a result of the GATT Trade Related Intellectual Property or "TRIPs" agreement) further provide for "moral" rights, which are rights in addition to copyrights possessed by authors, such as the right to have their work acknowledged and not be disparaged. While copyright is normally assigned or licensed to the publisher, authors generally retain their moral rights (although in some jurisdictions these can be excluded under contract).
Some European countries also provide for artist resale rights, which mean that artists are entitled to a portion of the appreciation of the value of their work each time it is sold. These rights are granted on the background of a different tradition, which granted droits d'auteur rather than copyright also granting all creators various moral rights monopoly rights to publishers to sell printed works, the modern concept of copyright originated in 1710 with the British Statute of Anne. This statute first recognized that authors, rather than publishers, should be the primary beneficiary of such laws, and it included protections for consumers of printed work ensuring that publishers could not control their use after sale. It also limited the duration of such exclusive rights to 28 years, after which all works would pass into the public domain.
The Berne Convention of 1886 first established the recognition of copyrights between sovereign nations. (Copyright protection was also provided by the Universal Copyright Convention of 1952, but that convention is today largely of historical interest.) Under the Berne convention, copyright is granted automatically to creative works; an author does not have to "register" or "apply for" copyright protection. As soon as the work is "fixed", that is, written or recorded on some physical medium, its author is automatically granted all exclusive rights to the work and any derivative works unless and until the author explicitly disclaims them, or until the copyright expires.
Some think the current copyright system doesn't work in the Information society. The general problem is that the current (international) copyright system undermines its own goal (Boyle 1996, 142). The concept of public domain, needed as a pool for future creators, is far too often forgotten or repressed, due to the strong position of the concept of the romantic author, and selective blindness for the possibilities concerning copyright that the Internet and computers offer. Except for unlimited copying, it offers, as said, also new ways formarketingand, more important, the possibilities of code; much depends of course of how code is used (code can be used and is in most of the cases also used in a positive way), but in various cases it threatens not only the public domain in a serious way, but is also ignored when talking about "restoring the balance" which is said to be gravely disturbed by the so called unlimited copying possibilities the Internet creates.  (http://akira.arts.kuleuven.ac.be/andreas/english_paper_gaidai.html)
Others believe that irrespective of contemporary advances in technology, copyright has been and remains the fundamental way by which authors, sculptors, artists, musicians and others can protect their creations from unauthorised copying. This view espouses that copyright serves as an incentive to creation of things such as books and art which are otherwise not protectable at law. Without the incentive afforded by protection, such creations would not exist.
In the US in 2003, controversial changes implemented by the Sonny Bono Copyright Term Extension Act extending the length of copyright protection under U.S. copyright law by 20 years were constitutionally challenged unsuccessfully in the Supreme Court.
Copyright law varies from country to country. For information on specific national copyright laws, see:
International treaties concerning copyright