We’ve had a slight hiccup with the distribution on the Cthulhu Mythos Encyclopedia, with the consequence that the prices for the book on Amazon have been driven up over $500 on speculation, and even higher from some foreign sellers. (The price for a copy in France, in fact, could get me another two-week French vacation!) This is the result of automatic pricing programs that compete against each other in a bidding war – you can read more about that here.
Elder Signs is working to resolve this situation. In the meantime, you can buy paperbacks from them at the regular $17.95 price. If you hesitated even slightly before dismissing the $500 price, I might recommend the signed and personalized hardcovers for $45, which are only available from their site.
I’ll update you when the situation changes.