Thank you for the information. I am putting them into separate folders just to be neat and keep track of my stuff.
If the Fire doesn't care what folder I put them into, then why would it continually refuse to display those 4 titles after putting them into the BOOKS folder numerous times and then seeing them in the DOCUMENTS folder they come up and work just fine with the other books. It shouldn't matter if the 4 titles are in the bOOKS folder, it should work. That's what I don't understand.