This book isn't published by one of the Agency 5, and thus not subject to agency pricing. List price is 25.99, but each retailer is offering it at a lower price. Checking Inkmesh (which doesn't think that B&N even carries the book) the typical price is roughly 18.00 (verified by checking each entry with the retailer, as Inkmesh isn't always up to date) with Amazon being the only exception. This means that B&N is 9.00 under list, and 4.00 under all competitors except Amazon. There's no guessing why Amazon has reduced the price so low, though one would guess it's a "loss leader" somehow. While it might be nice if B&N would reduce the cost to match Amazon, they are certainly being competitive in this instance and I see no reason to complain.