Color books with unknown contents red

This code should (SHOULD! please review carefully, since I'm not a code maestro) color all books that the player doesn't know the contents of -- either because the player cannot read at all, or because the player hasn't yet skimmed the book -- red.

I am open to suggestions of other colors. Red seemed like a good choice for "unknown." Maybe pink would be good, so it seems less urgent.
Oops.  I think this be a Leftover?