What are the best books on gardening and houseplants?

I’m wanting a new book or two on gardening, and one that has a bit of focus on houseplants and overwintering plants indoors. I’m also thinking about one with details on starting from seed and propagating. Which books are the most informative, with in-depth information and tips? I need something that will be useful to me in a cold climate.
Any links to good sites are also appreciated. I’m looking for a book, a hard copy, something that I can read in bed or when the internet’s out.