As noted in the introduction to 1 Kings, the books 1 Kings and 2 Kings in the Hebrew Old Testament are one book. That both books form one book is clear from the transition from 1 Kings to 2 Kings. The book 2 Kings begins with the mention of the death of Ahab, of which the author of the two books Kings reports in the last chapter of 1 Kings (1Kgs 22:29-4029So the king of Israel and Jehoshaphat king of Judah went up against Ramoth-gilead.30The king of Israel said to Jehoshaphat, “I will disguise myself and go into the battle, but you put on your robes.” So the king of Israel disguised himself and went into the battle.31Now the king of Aram had commanded the thirty-two captains of his chariots, saying, “Do not fight with small or great, but with the king of Israel alone.”32So when the captains of the chariots saw Jehoshaphat, they said, “Surely it is the king of Israel,” and they turned aside to fight against him, and Jehoshaphat cried out.33When the captains of the chariots saw that it was not the king of Israel, they turned back from pursuing him.34Now a certain man drew his bow at random and struck the king of Israel in a joint of the armor. So he said to the driver of his chariot, “Turn around and take me out of the fight; for I am severely wounded.”35The battle raged that day, and the king was propped up in his chariot in front of the Arameans, and died at evening, and the blood from the wound ran into the bottom of the chariot.36Then a cry passed throughout the army close to sunset, saying, “Every man to his city and every man to his country.”37So the king died and was brought to Samaria, and they buried the king in Samaria.38They washed the chariot by the pool of Samaria, and the dogs licked up his blood (now the harlots bathed themselves [there]), according to the word of the LORD which He spoke.39Now the rest of the acts of Ahab and all that he did and the ivory house which he built and all the cities which he built, are they not written in the Book of the Chronicles of the Kings of Israel?40So Ahab slept with his fathers, and Ahaziah his son became king in his place.). However, with this 1 Kings does not close. There follows a short report of the kingship of Jehoshaphat over Judah, probably because of his relationship with Ahab and Ahab’s son. After that some more announcements are made about Ahaziah, who succeeds his father Ahab as a king over Israel. That ends 1 Kings.
A plausible reason for a separation in the histories in one great book of Kings may be that it would otherwise should become too large a book. It is more difficult to give a plausible reason for making that separation as it has been done. As a possible reason it has been suggested that the separation was done the way it was done with the one great book of Samuel. 2 Samuel begins with the mention of the death of Saul and 2 Kings begins with the mention of the death of Ahab.
The description of the course of the histories in 2 Kings is done in a way that is somewhat comparable to the way in which the writer presents the course of the histories in 1 Kings to us. The book of 1 Kings begins with the blessing and wisdom of Solomon and ends with the follies of the kings of the northern tribes kingdom. The history of the ten tribes realm begins with Jeroboam, the ‘trendsetter’ for all the succeeding kings of that realm, and ends with Ahab, the king who completely apostatized from God.
The beginning of 2 Kings is essentially a record of the grace of God by Elisha for an apostate nation. Despite this grace, the people slide completely away from God. The book of 2 Kings ends with the deportation of the ten tribes by the king of Assyria and the deportation of the two tribes by the king of Babylon.