Jude's book is the 21st book of the New Testament. It consists one chapter with 25 verses. Jude calls himself the "brother of James". This has led to varying interpretations, as there are several people named James in the New Testament. It is possible that if he is the brother to the James who is listed in Mark 6:3, then Jude would be the brother of Jesus.
Jude, in his book, urges believers to stand firm against false teachers and false doctrines. He gives examples of God's judgment in the past upon sin, as well as a description of the evil lives of those false teachers. He closes in telling Christians to stand firm in the power of God, and that the power of God will keep us from falling.
Jude's book was probably written before 70 AD because there is no mention of the destruction of the Temple, which would have been appropriate in verses 5-7.
Next person in the Bible: Judith, wife of Esau