Malachi, Malachias, Malache or Mal'achi (; Hebrew: מַלְאָכִי, Modern: Malaḵay, Tiberian: Malʾāḵay, "Messenger", see malakh) was the traditional writer of the Book of Malachi, the last book of the Neviim (prophets) 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 (; , ) and speculated that he delivered his prophecies about 420 BCE, after the second return of Nehemiah from Persia (Book of Nehemiah ), or possibly before his return, comparing with ( with ).
In the Septuagint, or Greek Old Testament, the Prophetic Books are placed last, making the 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 ἐν χειρὶ ἀγγέλου αὐτοῦ, (by the hand of his messenger).
Because Malachi's name does not occur elsewhere in the Bible, some scholars doubt whether "Malachi" is intended to be the personal name of the prophet. None of the other prophetic books of the Hebrew Bible or the Greek Old Testament are anonymous. The form mal'akhi, signifies "my messenger"; it occurs in (compare to ). But this form of itself would hardly be appropriate as a proper name without some additional syllable such as Yah, whence mal'akhiah, i.e. "messenger of Elohim." Haggai, in fact, is expressly designated "messenger of Elohim" (). Besides, the superscriptions prefixed to the book, in both the Septuagint and the Vulgate, warrant the supposition that Malachi's full name ended with the syllable -yah. At the same time the Greek Old Testament translates the last clause of , "by the hand of his messenger," and the Targum reads, "by the hand of my angel, whose name is called Ezra the scribe." 
The Jews of his day ascribed the Book of Malachi, the last book of prophecy, to Ezra, but if Ezra's name was originally associated with the book, it would hardly have been dropped by the collectors of the prophetic canon who lived only a century or two after Ezra's time. Certain traditions ascribe the book to Zerubbabel and Nehemiah; others, still, to Malachi, whom they designate as a Levite and a member of the "Great Synagogue." Certain modern scholars, however, on the basis of the similarity of the title (compare to and ), declare it to be anonymous. Professor G.G. Cameron, suggests that the termination of the word "Malachi" is adjectival, and equivalent to the Latin angelicus, signifying "one charged with a message or mission" (a missionary). The term would thus be an official title, and the thought would not be unsuitable to one whose message closed the prophetical canon of the Old Testament.
Opinions vary as to the prophet's exact date, but nearly all scholars agree that Malachi prophesied during the Persian period, and after the reconstruction and dedication of the second temple in 516 BCE (compare ; , ). The prophet speaks of the "people's governor" (Hebrew "pechah", ), as do Haggai and Nehemiah ( ; ; ). The social conditions portrayed appear to be those of the period of the Restoration. More specifically, Malachi probably lived and labored during the times of Ezra and Nehemiah. The abuses which Malachi mentions in his writings correspond so exactly with those which Nehemiah found on his second visit to Jerusalem in 432 BCE () that it seems reasonably certain that he prophesied concurrently with Nehemiah or shortly after.
According to Rabbi W. Gunther Plaut, "Malachi describes a priesthood that is forgetful of its duties, a Temple that is underfunded because the people have lost interest in it, and a society in which Jewish men divorce their Jewish wives to marry out of the faith."