I had the good fortune to come across a copy of KotB for three bucks at the used bookstore in my hometown, which I visited last weekend. They also had two copies of the little red book and one copy of the little blue one, but I've got the mighty Cyclopedia on my shelf, so I passed on those.
I never knew that KotB was basically a campaign kickoff/mini-campaign setting. I really see why they used to call them modules.
I may post something more once I have actually read it. I feel like I'm spreading my attention too thin at the moment.