3.5.... if this topic is important to you (read: you're in sales, public speaker, or any other role that requires persuasion or magnetism.)
Obviously, the book is reflective of the time in which it was written so you have to kind of take some of the information with a grain of salt - but that doesn't mean there's no value here. Pick out what's useful and put the rest aside. However, there are some timeless universal principles in here with some exercises and habits that could definitely be of use to one who is seeking to increase their confidence and also to be able to read other individuals.
Lots of useful info on reading micro expressions in eyes, mouth & face tensions.
He starts out talking about eyes and some mumbo jumbo about eye color and magnetic properties... I though "oh oh, quack city". But once I got through those pages I did see the connection with eyes. Nothing to do with color, but with our eyes, we can process loads of information. You can look at a room, or you can really "see" a room and be able to recall loads of details from what may have been viewed for only seconds. That section of the book was very interesting and I definitely saw value in building the skills in the exercises.
Much of the book is a guide to what it takes to be someone with a commanding presence. Easy to pluck the timeless principles from what might be more "goofy" thoughts of that era.
It's not a "must read" but for those who are interested in the topic, it's at least worth a browse.