"Anyone who having been warned, still spends their hard earned on such a half-arsed product is either a mug or has more money than sense."
You're talking to aspiring pilots who may be prepared to trade the roof over their parents' heads for a lottery ticket.
I think the ratio of money to sense probably looks quite favourable towards buying a book
riddled with errors.
On a serious note, you do make a good point. I looked at a book on Amazon on the subject of mental maths (I think it was specifically for pilots). When I viewed the first few pages electronically before deciding whether or not to buy it, I found an error. I decided not to buy it as a result. The irony of a book that boasts of teaching rapid and precise mental calculation containing a basic arithmetic error in the first few pages did not fill me with enough confidence to part with my money. A book on technical issues and/or precise calculation should be reliable, otherwise the trust I place in the remainder of the content will not be to the degree it should. We're not talking about a simple spelling mistake or poor grammar here.
