Want to buy Hilary Mantel's Wolf Hall on Amazon.com? How about the new John Edwards tell-all by his former aide? Tough luck if you're looking for a digital copy. The online retailer has pulled those books along with others published by Macmillan from its shelves. At dispute is the price Amazon is selling e-books, which Macmillan's CEO says unfairly takes money away from the publisher. Beginning in March, Macmillan will sell its books digitally for $12.99 to $14.99, more than Amazon's $9.99 price for bestsellers. It is not known how long the books will remain unavailable.