The duration of copyright may vary from country to country according to the type of work (and the particular right in question). Although the Berne Convention sets a minimum duration of a copyright in a literary work equal to the life of the author plus 50 years, in most cases and countries today, the general rule is that copyright in literary, dramatic, musical or artistic works lasts for the life of the author and then until 31 December of the year 70 years after his or her death (usually referred to as “life plus 70”).
In some countries, specific rules may apply that alter or add to the general rule of life plus 70 years (for example, granting extensions for the period of World War II). In addition, some countries had different copyright terms that were in effect before adoption of the general rule. For example, the United States did not adopt a “life plus” copyright duration until 1978. These differences in national laws imply the fact that in some cases a specific work can still be in copyright in some countries but out of copyright (that is, in the public domain) in others.