A variorum, short for (editio) cum notis variorum, is a work that collates all known variants of a text. It is a work of textual criticism, whereby all variations and emendations are set side by side so that a reader can track how textual decisions have been made in the preparation of a text for publication. The Bible and the works of William Shakespeare have often been the subjects of variorum editions, although the same techniques have been applied with less frequency to many other works.