To get a sense of where the pricing issue now stands beyond the legal battles, I embarked on this simple exercise: I went to every major on-line retailer and a selection of traditional booksellers to find out what they were charging for Krugman's End This Depression Now. The title was published last April and reached as high as number 17 on the New York Times bestseller list for printed books. A starred review in Publishers Weekly concluded, "Krugman has consistently called for more liberal economic policies, but his wit and bipartisanship ensure that this book will appeal to a broad swath of readers from the Left to the Right, from the 99% to the 1%." According to Norton, the book has sold 30,000 copies in print, with e-book sales of 25,000. The list price for the book is $24.95, and every bookstore I called is selling it at that price. You can also order it directly from the publisher's website, but that comes with a shipping charge and sales tax where required.

Here is where the pricing becomes interesting. Amazon's hardcover price is $14.71, with no shipping charge for customers who pay an annual fee of $79 for Amazon Prime and two-day delivery. The Kindle edition is $9.48. At BN.com the hardcover is $14.71, but the e-book price is $13.72 (BN.com has free shipping for orders over $25). Moreover, in the Barnes & Noble bookstore, the hardcover is $24.95. On Apple's iBook, the price is $11.99. The Sony store charges $14.99, and on Kobo, which was recently named the e-book provider in the coming year for independent booksellers, the price was $15.49. Only Google Play matched Amazon at $9.48.

So, given these choices, what would you do? To some extent, the decision seems to depend on the reading device that customers purchase, with Amazon rolling out successively more affordable versions of its Kindles, most recently on September 6. Writing in the Wall Street Journal, Greg Bensinger said that while the latest group of Kindle Fires "included technologies that are already available in many other tablets, Amazon's new products stood out for their low prices, especially compared with Apple's popular iPads." Publishers believe that Amazon's goal is to condition its millions of customers to the lowest prices available for the hardware it sells and the content they carry, with the ultimate intention of driving vendors to accept less for what they sell. Mike Shatzkin, an oft-quoted publishing consultant, told the New York Times, "I think everybody competing with Amazon in the ebook market had better fasten their seatbelts."

In her opinion, approving the DOJ settlement with the publishers, Judge Denise Cote removed any obstacle to discounting with the argument that consumers have the right to expect the lowest possible price. "It is not the place of the court," she wrote, "to protect these bookstores and other stakeholders from the vicissitudes of a competitive market." For now, the estimable output of W. W. Norton, including Krugman's End This Depression Now, will continue to be available at a variety of prices. But over the longer term, with possibly serious consequences for the viability of publishers and booksellers, the odds favor the public's instinct to get the best bargain. To reiterate a crucial point I have made before: Publishers will always need the revenue to support authors and the staffs that edit, produce, and market their books, and to provide a reasonable profit for their owners. If the squeeze becomes too tight, the result will be fewer books that matter -- like End This Depression Now -- whether in print or digital formats.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.