A signature mark, in traditional bookbinding, is a letter, number or combination of either or both, which is printed at the bottom of the first page, or leaf, of a section.
The section is itself referred to as a signature, also called collation or gathering.[1]
The aim is to ensure that the binder can order the pages and sections in the correct order. Often the letters of the Latin alphabet were used.
The practice has been superseded by advances in printing and bookbinding technology. As a result, signature marks are rarely found in modern books.[2]