This description of Book of Zephaniah is from Easton's Bible Dictionary.
Zephaniah: Jehovah has concealed, or Jehovah of darkness. The son of Cushi, and great-grandson of Hezekiah, and the ninth in the order of the Minor Prophets. He prophesied in the days of Josiah, king of Judah (B.C. 641-610), and was contemporary with Jeremiah, with whom he had much in common. The book of his prophecies consists of:
An introduction (Zephaniah 1:1-6), announcing the judgment of the world, and the judgment upon Israel, because of their transgressions.
The description of the judgment (Zephaniah 1:7-18).
An exhortation to seek God while there is still time (Zephaniah 2:1-3).
The announcement of judgment on the heathen (Zephaniah 2:4-15).
The hopeless misery of Jerusalem (Zephaniah 3:1-7).