After I decided to take the wise advice offered on this Forum, I researched dehumidifiers like crazy and finally settled on this model: http://www.amazon.com/Soleus-Air-CFM-40 ... 94&sr=8-10
So far, it works like a charm. It's quiet, easy to empty and light. I'd heartily recommend it. In fact, now that I know it's a good model I'll be buying a few more.
As for the girlfriend, I never have to worry about her dusting the tomes with a damp rag, as she wears a special electronic collar that gives her a jolt should she come within a yard of the bookshelves. Unfortunately, I still have to worry about helping her regain consciousness when she happens to stray too close, but it's a decent compromise, I'd say, and she's a very good sport about it.
Thanks again to everyone for taking the time to help me solve my sticky icky problem.