This article talks about the end of the cassette for "talking books". http://www.nytimes.com/2008/07/28/business/media/28cassette.html
It has some interesting statistics in it.
Richard
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.