Both 1 and 2 Kings contain the history of Israel's kings from the ministry of Samuel to the Babylonian captivity. It is not known who wrote Kings, but whoever did write it, the books were compiled from records that are no longer available – such as the book of the acts of Solomon, and the book of the chronicles of the kings of Israel and Judah.
So, we refer to 1 Kings as the third book in the group of four books that tells the history of Israel during the time they were ruled by kings. First Kings begins with Solomon being chosen as king after David and covers approximately 120 years of history and ends with the story of Ahab - one of the most wicked kings in Israel's history.
The story of Solomon is also told in the first half of 1 Kings – first as a leader of Israel at a time of extraordinary success, and later as a spiritually fallen leader who led his people down the same path. By the end of this leaders reign, Israel experienced a spiritual and temporal decline, which resulted in the division of Solomon's kingdom within a year of his death.
The second half of 1 Kings explains Israel's divided kingdom and relays the history of how the political leaders kept the covenants they made with God. However, the key focus is on the kings who were most notable in either keeping or not keeping the covenants and on the prophets who preached to them. Great lessons of good and bad examples can be learned in 1 Kings.