Most scholars argue that the author was not Jeremiah, but a Hellenistic Jew who lived in Alexandria. Whoever the author, the work was written with a serious practical purpose: to instruct the Jews not to worship the gods of the Babylonians, but to worship only the Lord.
The date of this work is uncertain. It is interesting to note that 2 Maccabees may be referring to this letter in chapter 2 verses 1-3. However, the reference in 2 Maccabees is disputed by Fritzsche, Gifford, Shrer, and others.
The letter (epistle) is included as a discrete unit in the Septuagint. There is no evidence of it ever having been canonical in the Jewish tradition.
The earliest evidence we have of the question of its canonicity arising in Christian tradition is in the work of Origen of Alexandria, as reported by Eusebius in his Church History. Origen listed Lamentations and the Letter of Jeremiah as one unit with the Book of Jeremiah proper, among "the canonical books as the Hebrews have handed them down".
Jerome provided the majority of the translation work for the vulgar (popular) Latin translation of the Bible, called the Vulgate Bible. In view of the fact that no Hebrew text was available, Jerome refused to consider the Epistle of Jeremiah, as the other books he called apocryphal, canonical.
Despite Jerome's reservations, the epistle is included as chapter 6 of the book of Baruch in the Old Testament of the Vulgate. The Authorized King James Version follows the same practice, while placing Baruch in the Apocrypha section. In the Ethiopian Orthodox canon, it forms part of the "Rest of Jeremiah", along with 4 Baruch (also known as the Paraleipomena of Jeremiah).
The epistle is one of three deuterocanonical books found among the Dead Sea scrolls (see Tanakh at Qumran). (The other two are Ben Sira and Tobit.) The portion of the epistle discovered at Qumran was written in Greek. This does not preclude the possibility of the text being based on a prior Hebrew or Aramaic text. However, the only text available to us has dozens of linguistic features available in Greek, but not in Hebrew, hence introductions of a Greek editor, not required for minimalist translation.
In verse 70, with rare irony, the author compares an idol to a scarecrow—impotent to protect, but deluding to the imagination. Babylonians are believed to have carried their idols around on their shoulders ; some scholars point to this description as evidence that Jeremiah may have actually written this work. Adding to this, the Jewish historian Josephus mentions a legend where Jeremiah sends a letter to the exiles in Babylon and commands that it be thrown into the sea after it has been delivered.