BIBLE FACTOID: What books of the Bible do not use the word "God"?

The Bible is the story of God's relationship with humankind, from our creation to our salvation to our ultimate fate in a New Heaven and New Earth. So are there any books of the Bible that don't actually mention "God"?

 Yes! The two books are "Esther" and "Song of Solomon". (But the fact that His name is not mentioned, doesn't mean they're not about Him!)