Not read the book, but I suspect BS. When I was at the LRRP School in 88 I met an old time SF Team guy who had done some weird experimental training back in the late 70's early 80's. Some of it was all pretty banal - sleep deprivation, meditation versus low temperatures etc. Bottom line, only a small number of folks saw benefit. It couldn't be taught, and it was no where near an exact science, so great if your a rich middle aged divorcee from up-state NY, but BS for an Army. I wait to be convinced!