Linda has has books and videos out about horses for years, using the ttouch, I used some of it on my horse and her calming training styles are really useful.
I think she is on to something.

she has a book out about how to find out about the general personality of a horse by looking at the shape of the head, ears, nose and other facial features and shapes - it does apply from what I have noticed with the horses I have had.

my wonderful first horse had a awesome personality and he fit in with her descriptions.
I didn't get the book until after I got the horse I have now though...

my horse now fits in to all the sensitive, high strung, flighty, unpredictable...
but I keep her anyway.