A facsimile is a copy or reproduction of an old book, manuscript, map, art print, or other item of historical value that is as true to the original source as possible. It differs from other forms of reproduction by attempting to replicate the source as accurately as possible in scale, color, condition, and other material qualities. For books and manuscripts, this also entails a complete copy of all pages; hence, an incomplete copy is a "partial facsimile". Facsimiles are sometimes used by scholars to research a source that they do not have access to otherwise, and by museums and archives for media preservation and conservation. Many are sold commercially, often accompanied by a volume of commentary. They may be produced in limited editions, typically of 500–2,000 copies, and cost the equivalent of a few thousand United States dollars. The term "fax" is a shortened form of "facsimile" though most faxes are not reproductions of the quality expected in a true facsimile.

A manuscript was, traditionally, any document written by hand or typewritten, as opposed to mechanically printed or reproduced in some indirect or automated way. More recently, the term has come to be understood to further include any written, typed, or word-processed copy of an author's work, as distinguished from the rendition as a printed version of the same.