The Book of Baruch is the only deuterocanonical text modeled after other prophetic books of the Old Testament. It is the confession and repentance of losing the way toward everlasting life in and with God, lamenting the slide toward idolatry and human centric values and the loss of Judaic Law, God's gift of wisdom.
It is the attributed author's name: Baruch ben Neriah, or Son of Neriah
Presumably it was written in the 6th century BCE at the time of the Babylonian siege of Jerusalem, as stated in the first verse, by Baruch ben Neriah the Jewish Aristocrat, scribe, and secretary and friend to the prophet Jeremiah. Though translated from Greek, it was probably written in Hebrew or Aramaic as evidenced by the translation.