Originally Posted by HarryT
The Kindle does have a back button. Amazon have cunningly hidden it by putting the word "Back" on it. Most reading devices do have a "Back" facility; I certainly wouldn't lose any sleep over supporting those few broken devices that lack such a facility, personally.
PG is Project Gutenberg.
When you say "most" have a back facility, what do you mean? If my most sold then yes, the Amazon Kindles have a back button. If you mean the most models then I would disagree. Where does your data come from?