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 22:29-40). 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.