Rarely it is scientifically proven, and more often it is just a restatement from other books that themselves have no scientific basis (david goggins ist the most prominent one). I believe everyone will gain something by reading this but everyone will also think that they are wasting their time. I get the feeling the author is bigheaded, arrogant or just creats make-believe books without any real foundation (and the author seems to make a lot of these...). (English just doesnt have the correct word for it, but i jope my point still comes across)