I can't believe people think it's woo-woo or anti-scientific, though, after reading it. Sarno's thesis is basically "we haven't found a physical cause for most chronic pain conditions, so why not the brain?".
Anxiety sufferers can fool themselves into thinking they're having a heart attack and hyperventilate. Why is it crazy or anti-scientific to think that the same can cause other symptoms?
That makes more sense than I was expecting. In particular, pain must be felt in the brain. That is, my body can be suffering some trauma, but if the nerve signals don't make it to the brain, or the brain doesn't interpret them as pain, then I don't feel pain. (This is true of third-degree burns - they don't hurt very much, because the nerves got destroyed, so you don't feel how bad the burn is.)
But if the body isn't under (known) trauma, but the patient is experiencing pain, maybe the brain is a reasonable place to look...