In the books of 1 and 2 Kings, there are quite a few places where the author refers to "the Book of the Chronicles of the Kings of Judah" or "the Book of the Chronicles of the Kings of Israel".
"Now the rest of the acts of Jeroboam, how he made war and how he reigned, behold, they are written in the Book of the Chronicles of the Kings of Israel. 1 Kings 14:19 NASB
Now the rest of the acts of Rehoboam and all that he did, are they not written in the Book of the Chronicles of the Kings of Judah? 1 Kings 14:29 NASB
Immediately following the books of 1 and 2 Kings are two books referred to as 1 and 2 Chronicles. Are these the books to which 1 and 2 Kings refer or are they referring to other books that are not in the Bible and/or maybe lost to us?