The Book of Nahum is a book of prophecy in the Old Testament of the Bible. It was written by the Prophet Nahum, whom the book is named for. The is entirely composed of a prophecy in form of a vision to Nahum, concerning the destruction of the city of Nineveh, Assyria's capital.
The Book of Nahum is entirely a prophecy. It is written in a very prophetic and exclamatory style that poetically describes the destruction of Nineveh. While not specifically the historical account genre, it does include several factual historical elements being a prophecy.