Good video. Especially about the book height and getting up again at the end. The lying down method is not optimum. Also the real benefit comes from using Constructive Rest really often. A minute at a time is enough. Your thinking should be done in action while going about your daily activities. I explain more in my videos on YouTube (where I'm known as "Backmagician") youtube.com/view_play_list?p=CC4C9F736BAF2E79