If you're just tuning in, you may have missed the part where I pointed out that book publishing is a 100% returnable industry, meaning that any stock a retailer takes on can be returned to the vendor (i.e. publisher) for full credit if they're unable to move it. If Joe's National Book Chain takes ten thousand copies of Sue Celebrity's new hardcover diet book, Lose Weight By Perhaps Eating Less And Going to the Gym Once in Awhile, but only manages to sell two thousand (far-fetched, I know, given the title), guess what? Eight thousand copies are going back to the publisher. Not all at once, mind you, but if the book came out in time for the holiday season, a sizable portion of the overstock will go back to the house in January, with the rest following by the time the paperback comes out eight months to a year later.
If the fiscal fourth quarter is the champagne and caviar of the publishing industry, the fiscal first quarter is the hangover and stale fish egg taste in its mouth. January and February usually see heavy returns and lower consumer spending (President's Day is not the new Christmas), and with the holiday rush over and the beach read wave not yet begun, the industry feels the weight of each and every one of those returns. As I've mentioned before, publishers hate to keep returned stock around, and so most of what gets sent back either gets remaindered or destroyed.
The bad news: your book(s) (if you have any out there) will probably suffer this fate sooner or later (sooner if your book hit the shelves this past fall). The good news: unless you're kind of a big deal, most accounts probably didn't order a huge number of copies of your book, so there aren't that many to return! (It's books by big, fancy authors like Patricia Cornwell, Dan Brown, James Patterson, &c who will constitute the bulk of returned stock). So take heart, gentle readers: if your book gets eaten by the Great Cantankerous Pulping Machine™, it's going to be keeping good (or, at least, commercially successful) company in its stomach.