Nachum HaNavi was a prophet living during the reign of Minashe king of Yehuda. His prophesies are recorded in the seventh book of the Teri Asar where he prophisizes about the destruction of Ninveh. He is sometimes called Nachum HaElokshi after his birth place; Eloksh. Nachum was a student of Yoel and a teacher of Chavakuk.
 Book of Nachum
The Book of Nachum is the seventh in the set of the 'Minor Prophets'. It discusses the greatness of Hashem and the forthcoming destruction of Nenveh the capital of Assyria due to their return to evil ways after a short repentance following the prophecy of Yonah. It consists of 4 chapters containing a total of 47 verses.
 Destruction of Nenveh
Nachum predicted that Nenveh would be destroyed due to a massive flood from the Chidekel river. Indeed the walls of Ninveh withstood all enemy assaults and battery until a powerful rain flooded the Chidekel River, flooding the city and fracturing its walls, allowing the sieging enemy forces to enter and capture the city.
Nachum Hanavi is buried in Kifar Nachum which is named after him.