Not a surprise at all. It's far too difficult for the average weekend golfer. If the list were for the most important instructional books for Teachers, The Golfing Machine would be right at the top.
Kevin
I think I was sarcastic when I expressed surprise. The book is very important for instructors and very dedicated and clever golfers, but for a larger public I think there should be a TGM light or a book with more explanations (a Yoda book)..