Textual criticism is the study of different copies of books or manuscripts. The purpose is to find the original, and see what changes were made to the later versions.
Textual criticism started with the study of the Bible, but now these techniques are used to study many texts.
The basic problem, as described by Paul Maas, is as follows:
The lack of autograph manuscripts applies to many cultures other than Greek and Roman. In such a situation, a key objective becomes the identification of the first exemplar before any split in the tradition. That exemplar is known as the archetype. "If we succeed in establishing the text of [the archetype], the reconstruction of the original is considerably advanced".pp22–23
The textual critic's ultimate objective is the production of a "critical edition". This contains a text most closely approximating the original, which is accompanied by a critical apparatus that presents: