What is the "Penultimate Book" in the Bible?

The penultimate book in the Bible is Jude, also called the Epistle of Jude.

Jude appears immediately before Revelation in the standard ordering of the Christian Bible, making it the second-to-last biblical book. It is also the final short letter among the General Epistles of the New Testament. The book contains a single chapter and is traditionally associated with Jude, a servant of Jesus and brother of James.

The letter warns Christian communities about false teachers and urges believers to remain faithful. It uses examples of divine judgment from Israelite tradition and refers to traditions associated with the archangel Michael and the Book of Enoch. Scholars continue to debate the author's precise identity and date of composition.

A common mix-up is naming Revelation as the penultimate book. Revelation is the final book in the usual Christian Bible, while Jude comes directly before it. Jude is also penultimate within the New Testament, which contains 27 books.