Copyright is exclusivity rights, held by the creator of an original work. This typically includes rights to adapt, copy, and distribute the work in question. Generally speaking, copyright kicks in when the original work is created. It does not need to be registered, and the original owner has exclusive rights to control exploitation of their work for a period of time. When the time has lapsed, the work enters the public domain.
There are exceptions and limitations to copyright. For instance, fair use. Fair use does not require permission from the original owner. However, other uses do require permission. The original owner may license or even permanently transfer/assign their exclusion right(s) to others.
In the beginning, copyright law only applied to copying books. However, as time passed, derivative works and translations also fell under copyright law. Today, copyright applies to a broad range of items that includes, but is not limited to, paintings, photos, maps, sheet music, sound recording, computer programs, motion pictures and architectural drawings.
Copyright laws in the 21st century are largely standardized as a result of regional and international agreements, and in many nations there is consistency when it comes to copyright laws. However, each jurisdiction does have distinct laws, rules and regulations dealing with this matter.