There’s a tradition in the publishing industry of paying writers “by the word,” but a group of the nation’s largest book publishers, along with one of its major computer makers, is now accused of making readers pay excessive prices for their words.

The issue is the cost of “ebooks,” electronic versions of literary works once only available on actual paper.

Now, virtual books that can be downloaded in seconds and called up on portable tablets with huge storage capacities are a billion-dollar market.

With sales expected to triple over the next three years, the publishers and Apple, Inc., whose iPad readers are a major competitor in the ebook market (along with the Barnes & Noble Nook and Amazon’s various Kindle models), were feeling huge market pressures.

The competition was primarily coming from Amazon, which had offered electronic versions of books for an initial price of $9.99, far below the list price of new hardcovers, now approaching $30 or more. Amazon’s customer base, which appreciated the lower cost of versions that, after all, did not have to be printed on paper or sold via physical stores, snapped up the electronic books by the millions.

So, the Justice Department alleges, publishers like Simon & Schuster, HarperCollins and Penguin, along with others, conspired with Apple to seize control of the ebook market from Amazon and drive up prices on downloadable versions.

Some of the publishers have settled with Justice without admitting liability, while Apple and others are fighting the conspiracy charges.

The DOJ says the companies feared that Amazon’s low prices would cause consumers to demand reductions on the cost of all books, and eventually lead Amazon to sell content directly to readers, bypassing traditional publishers and aiding Kindle sales.

The publishers and Apple argue that Amazon’s market dominance was leading to it becoming a monopoly, driving competitors out of business by selling below cost.

But the DOJ says retailers were being denied the right to set their own prices by the conspiracy. That seems right: Consumers, not cartels, deserve to benefit from lower-cost methods.

It’s not only the bottom line, it’s the last word.