Forgery is the process of making or adapting objects or documents (see false document), with the intention to deceive (fraud is the use of objects obtained through forgery). Copies, studio replicas, and reproductions are not considered forgeries, though they may later become forgeries through knowing and willful mis-attributions. In the 16th century imitators of Albrecht Dürer's style of printmaking improved the market for their own prints by signing them "AD", making them forgeries.
In the 20th century the art market made forgeries highly profitable. There are widespread forgeries of especially valued artists, such as drawings meant to be by Picasso, Klee, and Matisse.
This usage of 'forgery' does not derive from metalwork done at a 'forge', but it has a parallel history. A sense of "to counterfeit" is already in the Anglo-French verb forger "falsify."
A forgery is essentially concerned with a produced or altered object. Where the prime concern of a forgery is less focused on the object itself— what it is worth or what it "proves"— than on a tacit statement of criticism that is revealed by the reactions the object provokes in others, then the larger process is a hoax. In a hoax, a cultural meme, such as a rumor, or a genuine object "planted" in a concocted situation, may substitute for a forged physical object.
Literary forgery - these literary forgeries all had some affect on the course of cultural history. Other literary forgeries, such as the Hitler diaries, briefly achieve wide notoriety, without affecting subsequent history; they are brought together as literary hoaxes.
Forger N.G., Hodges L., Breedlove S.M. (1993) The ontogeny of calcitonin gene-related peptide immunoreactivity in rat lumbar motoneurons: Delayed appearance and sexual dimorphism in the spinal nucleus of the bulbocavernosus.
Forger N.G., Roberts S.L., Wong V., Breedlove S.M. (1993) Ciliary neurotrophic factor rescues rat motoneurons during developmental cell death.
Forger, N.G., Howell M.L., Bengston L., MacKenzie L., DeChiara T.M., Yancopoulos G.D. (1997) Sexual dimorphism in the spinal cord is absent in mice lacking the ciliary neurotrophic factor receptor.