Good question. Saw those myself and thought it was an odd item to use as a scam. Trawled the interwebs and found that they do appear to be legit.
Makes me wonder where they came from though. No-one would be writing new Amiga books in this day and age and the sheer number of topics they cover is boggling - even AmigaUX has a dedicated book.
Would be interesting to hear from someone who owns one of them to get more information re: publication dates etc.
