Man, the New York publishing industry is going to be livid when it wakes up tomorrow morning. Publisher's Weekly says:

During the evening of November 8, buy buttons were removed from a number of publishers' Kindle titles, including Hachette, Random House, Penguin, Simon & Schuster, Macmillan, and HarperCollins.

According to reports on Twitter, if you've bought Kindle books already, they're still available to you. You just can't buy new ones from the six biggest publishers in the industry. Kindle books from other publishers like Harlequin remain buy-able, so romance fans can rest easy. hasn't commented or released any statement about the matter, so the cause—whether it's a glitch, an infrastructure failure, or if is starting a fight with the Big Six publishers—remains unknown at this hour.