The Megillat Esther (Book of Esther) became the last of the 24 books of the Tanakh to be canonized by the Sages of the Great Assembly.
The Greek book of Esther, included in the Septuagint, is a retelling of the events of the Hebrew Book of Esther rather than a translation and records additional traditions which do not appear in original Hebrew version, in particular the identification of Ahasuerus with Artaxerxes and details of various letters.