Encyclopaedia Britannica is to stop publishing print editions of its flagship encyclopaedia for the first time since the sets were originally published more than 200 years ago.
The book-form of Encyclopaedia Britannica has been in print since it was first published in Edinburgh in 1768. It will stop being available when the current stock runs out, the company says.
The Chicago-based company will continue to offer digital versions of the encyclopaedia.
It said the end of the printed, 32-volume set had been foreseen for some time.
"This has nothing to do with Wikipedia or Google," Encyclopaedia Britannica Inc president Jorge Cauz said. "This has to do with the fact that now Britannica sells its digital products to a large number of people."
The top year for the printed encyclopaedia was 1990, when 120,000 sets were sold, Mr Cauz said. That number fell to 40,000 just six years later in 1996. The company started exploring digital publishing the 1970s. The first CD-ROM version was published in 1989 and a version went online in 1994.
The final hardcover encyclopaedia set is available for sale at Britannica's website for 1,395 dollars (£894).
"The sales of printed encyclopaedias have been negligible for several years," Mr Cauz said. "We knew this was going to come."
The company plans to mark the end of the print version by making the contents of its website available free for one week starting on Tuesday. Online versions of the encyclopaedia now serve more than 100 million people around the world, the company says, and are available on mobile devices.
Britannica has thousands of experts contributors from around the world, including Nobel laureates and world leaders such as former US president Bill Clinton and Archbishop Desmond Tutu. It also has a staff of more than 100 editors.
The Press Association, photo: BostonTx