1 Kings is only the first half of the book called Melakhim ("Kings") in the Hebrew Bible. Christian translators split that book in 2, so now we have 1 Kings—or, more properly, the First Book of the Kings in most Protestant translations of the Bible. In Catholic translations, it's actually called the Third Book of the Kings (because the books known as 1 and 2 Samuel in Protestant versions are called 1 and 2 Kings in Catholic versions). First, third, twelfth… call it whatever you want. It's all the same story all about (say it with us) a bunch of kings. (source)