Works in the public domain are those whose exclusive intellectual property rights have expired,^[1] have been forfeited,^[2] or are inapplicable.^[3][4] For example, the works of Shakespeare and Beethoven, and most of the early silent films, are all now in the public domain by leaving the copyright term.^[1] Examples for works not covered by copyright which are therefore in the public domain, are the formulae of Newtonian physics, cooking recipes^[3] and all software before 1974.^[5] Examples for works actively dedicated into public domain by their authors are the Serpent encryption reference implementation,^[6] NIH‘s ImageJ,^[7] and the CIA‘s The World Factbook.^[8] The term is not normally applied to situations where the creator of a work retains residual rights, in which case use of the work is referred to as “under license” or “with permission”.

As rights are country-based and vary, a work may be subject to rights in one country and be in the public domain in another. Some rights depend on registrations on a country-by-country basis, and the absence of registration in a particular country, if required, creates public domain status for a work in that country.

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