The CD-ROM came from nowhere and destroyed the printed encyclopedia business. Whereas Britannica sells for $1,500 to $2,000 per set (depending on the quality of the binding), CD-ROM encyclopedias, such as Encarta, Grolier, and Compton, list for $50 to $70. But almost no one pays even that: the vast majority of copies are given away to promote the sale of computers and peripherals.