I have noticed a nagging weakness that shows up in a lot of riders. They have an aversion to studying theory.
He spent a lifetime studying and traveled the world in search of "true" dressage. This is what he found.
Just released in 2018! At the core of this book is a series of 'state of the art' experiments in which the author participated, designed to establish whether certain classical ideas about true collection could be scientifically proved.