Malachi, Malachias, was the writer of the Book of Malachi, the last book of the Neviim section in the Hebrew Bible. No allusion is made to him by Ezra, however, and he does not directly mention the restoration of the temple. The editors of the 1906 Jewish Encyclopedia implied that he prophesied after Haggai and Zechariah (Malachi 1:10; 3:1, 3:10) and speculated that he delivered his prophecies about 420 BCE, after the second return of Nehemiah from Persia (Book of Nehemiah 13:6), or possibly before his return, comparing Malachi 2:8 with Nehemiah 13:15 (Malachi 2:10-16 with Nehemiah 13:23).
In the Christian Greek Old Testament, the Prophetic Books are placed last, making Book of Malachi the last protocanonical book before the Deuterocanonical books or The New Testament. According to the 1897 Easton’s Bible Dictionary, it is possible that Malachi is not a proper name, but simply means “messenger of YHWH”. The Greek Old Testament superscription is (by the hand of his messenger).
The Book of Machi: