Malachi (or Malachias; Hebrew: מַלְאָכִי, Malʾaḫi, Mál'akhî) is the last book of the Neviim contained in the Tanakh, the last of the twelve minor prophets (canonically) and the final book of the Neviim. In the Christian ordering, the grouping of the Prophetic Books is the last section of the Old Testament, making Malachi the last book before the New Testament.
The book is commonly attributed to a prophet by the name of Malachi. Although the appellation Malachi has frequently been understood as a proper name, its Hebrew meaning is simply "My [i.e., God's] messenger" (or 'His messenger' in the Septuagint) and may not be the author's name at all. The sobriquet occurs in the superscription at 1:1 and in 3:1, although it is highly unlikely that the word refers to the same character in both of these references. Thus, there is substantial debate regarding the identity of the book's author. One of the Targums identifies Ezra (or Esdras) as the author of Malachi. St. Jerome suggests this may be because Ezra is seen as an intermediary between the prophets and the 'great synagogue'. There is, however, no historical evidence yet to support this claim.
Some scholars note affinities between Zechariah 9–14 and the Book of Malachi. Zechariah 9, Zechariah 12, and Malachi 1 are all introduced as The word of Elohim. Many scholars argue that this collection originally consisted of three independent and anonymous prophecies, two of which were subsequently appended to the Book of Zechariah (as what scholars refer to as Deutero-Zechariah) with the third becoming the Book of Malachi. As a result, most scholars consider the Book of Malachi to be the work of a single author who may or may not have been identified by the title Malachi. The present division of the oracles results in a total of twelve books of minor prophets—a number parallelling the sons of Jacob who became the heads of the twelve tribes of Israel. The Catholic Encyclopedia asserts that "We are no doubt in presence of an abbreviation of the name Mál'akhîyah, that is Messenger of Elohim.