Jude, a slave of Jesus Christ and a flesh brother of James (the author of the Epistle of James) and of the Lord (v. 1 and note 1).

Approximately A.D. 69, before the destruction of Jerusalem and around the same time as the writing of 2 Peter, as indicated by allusions to the decline of the church similar to those found in 2 Pet. 2.

Jerusalem or Judea, though this is difficult to establish with certainty.

The Jewish believers, as indicated by the book's Jewish tone.