Book of Joel in Easton's Bible Dictionary

Joel was probably a resident in Judah, as his commission was to that people. He makes frequent mention of Judah and Jerusalem (1:14; 2:1, 15, 32; 3:1, 12, 17, 20, 21). He probably flourished in the reign of Uzziah (about B.C. 800), and was contemporary with Amos and Isaiah. The contents of this book are, (1.) A prophecy of a great public calamity then impending over the land, consisting of a want of water and an extraordinary plague of locusts (1:1-2:11). (2.) The prophet then calls on his countrymen to repent and to turn to God, assuring them of his readiness to forgive (2:12-17), and foretelling the restoration of the land to its accustomed fruitfulness (18-26). (3.) Then follows a Messianic prophecy, quoted by Peter (Acts 2:39). (4.) Finally, the prophet foretells portents and judgments as destined to fall on the enemies of God (ch. 3, but in the Hebrew text 4).

Link: https://bible-history.com/eastons/J/Joel,+Book+of/