Well the way to protect books from termites in your case is to protect your home from termites.

Visible termites inside your home is never a good sign. It is generally accepted that at the first indication of termites, you should immediately contract a reputable pest control company to come and handle that shit before it destroys the building - let alone your books!

And if it's not your home and your landlord won't do what's necessary here? Move. Move, before the place comes crashing down on your head in a cloud of sawdust and half-eaten beams.

Termites should never be a problem, and if they are, they're a much bigger problem than just your books.