If you are interested in clays and want to know how the pros do it....this is your book. Practice the principles and it will also make you a better field shot.
Not much on ballistic minutia that many seem to think is so important....the perfect pattern means nothing if you can't place it in the correct place when it means something....but everything on hitting. Using vision, efficient handling of the shotgun and how it all ties together to hit more targets or Birds.