Joining their counterparts in the film industry, large book publishing houses are the latest to take aim at users of the BitTorrent file-sharing protocol. John Wiley and Sons, the publisher of the popular "For Dummies" how-to book series, is suing 27 Bit Torrent users for downloading PDF files of the books, thereby infringing on Wiley's copyrights.

How extensive is the alleged book piracy? Demonoid.me users are said to have swapped copies of Photoshop CS5 All-In-One For Dummies more than 74,000 times, according to the lawsuit.

The defendants, all of whom reside in New York state, are being sued for copyright and trademark infringement, as well as trademark counterfeiting, which the company claims may dilute the quality of its brand and thus incur even further costs.

This is a first for the publishing industry, who are following in the footsteps of Hollywood. Most famously, tens of thousands of users who used BitTorrent to download the widely-acclaimed and award-winning film The Hurt Locker were sued by the film's producers. Many of those defendants settled out of court, as is common in cases like these.

Despite the popularity of legitimate e-book marketplaces like Amazon's Kindle Store and Apple's iBooks, digital book piracy has grown in recent years, with some best-sellers being illegally downloaded hundreds of thousands of times.

It remains to be seen how this case unfolds, or if other book publishers follow Wiley in the practice of suing BitTorrent users for copyright infringement.