Originally Posted by gweminence
Actually, I've been putting them in the books folder, and half of them show up in the reader, while those that don't show up under the docs tab, despite being in the books folder.
I agree, Books or Documents
So far, all my Calibre MOBIs (even those from ePubs) show up as Books, no matter which of the two folders they are in. A PDF shows up under Docs though.