Sure it's an old method. But this is not about the method at all - the 'application' of the method is what is damn clever. It's never been used this way before ever - and therein lies its beauty.
Here, not only do 16 fantastic routines get added to my toolbox, but the additional subtleties and embellishments - so cool to read and apply.
Imo, full value for my money - 'cuz I'm actually using these.