It looks like Critical Conversations may have been selling faster than expected! They appear to be out of stock.
Until they re-stock, I suggest you try the publisher, CBD. or Barnes and Noble; or go the ebook route, through Amazon or any of these sources.
If you’ve already bought it, please review it on Amazon. That helps the book a lot!
Note: I have no information on sales or inventory beyond what everyone can see on booksellers’ web pages. (Really.)