The short answer is: I don't know! Rethinking Worldview released last week, but it still shows up as a pre-order at Amazon.com. What's more, the delivery date Amazon is giving is in late December! I've been getting a lot of questions about this, so I figured I should share what I know.
First, the book has not been delayed. If you visit Crossway, you can place an order now and it ships within 2-3 days.
Apparently there's a glitch with Amazon, and the folks at Crossway tell me they are working to correct it. As soon as I receive more information, I'll post it here. In the meantime, those of you who have pre-ordered the book through Amazon, sit tight. We'll get everything worked out ASAP!