US publisher John Wiley & Sons is demanding a trial by jury of people accused of copying its books.
Papers filed in New York and revealed by the Torrent Freak news site said four defendants were involved.
The firm's lawyer said that he believed this would be the first trial of its kind based on the use of Bittorrent.
The peer-to-peer communications protocol allows users to upload and download files to each others' computers.
Wiley had previously filed 15 lawsuits to obtain the identities of about 200 people believed to have infringed the copyright of its titles.
It said in papers filed last October that users had "engaged in the illegal copying and distribution of Wiley's 'For Dummies' books through the peer-to-peer file sharing software known as Bittorrent".
Although it said that it was unable to give a precise figure for the amount of revenue lost, it described the sum as "enormous".
It noted that one title - Photoshop CS5 All-In-One For Dummies - had been downloaded 74,000 times over a 16-month period. The title is sold for £28.
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