This is early Ron Kurtz, reminds me of Stanley Kellerman's work, looking at the body to see psychological types. What is the posture? It all means something, we all grew up in systems that shaped us. There is much that meets the eye if we are trained to see it. It's good work, and people who work with bodies daily and know muscles begin to see it everywhere. I'm studying sensorimotor psychotherapy where there is also close attention to the body and movements. Pat Ogden, who developed sensorimotor psychotherapy, worked with Ron Kurtz and she is an expert on this way of seeing.
Seemed to be an introductory book to the subject of identifying psychological traits through physiological means. A lot of references to other studies; very general. I don't think I learned very much from this book, although the subject matter was interesting. I found the authors' discussion on their own bodies unbelievable, though ("I feel this." "You're right! I see that! I also see this!" "You're right! I feel that way!")
An interesting theory that the body posture and shape are closely related (by both cause and effect) to the mind and personality traits, and those are all related to the treatment of the body and will in childhood. I probably agree with it mostly. Many of the diagrams and claims about the postures in pictures were unclear.