Facial and gross expressions has been the vernacular of subcommunication mankind since some feel is the advent of awareness in the human condition. But it wasn't until the late 50s when Paul Ekman began his research into human nonverbal communication and began to literally code and catalog human body language in relation to situations and expressed emotions.
"Reading Faces" is essentially nothing more then the art of knowing what it means when someone moves a certain way, by using FACS, the facial analysis coding system we can quickly and concisely pair action units with basic emotions determined by the exercise of action units; or muscle groupings.
Reading faces can range from a deeply rewarding experience to a deeply disturbing one at times when you began to see the truth and deception in your daily life, my own personal experience was like unplugging from the matrix as I began to read the unconscience desires, fears, and dislikes of those around me.
What I did find, is that people lie a lot. Unfortunately the connotations of lying are almost universally negative, so it becomes easier for the adept to begin to view things in in a sort of detached spectrum of truth or untruth, and to continue to detach as much as possible from the actions of truth or untruth and use the subcommunications provided to attempt to delve the deeper meaning of what one is trying or unintentionally communicating.
And as well, there is no minimium commitment to practice this form of communication, simple awareness of a handful of key elements will weave themselves closely to you, as your own natural unconscience processing of this same information becomes a conscience one and you'll begin to apply your intuitions quickly and easily to things you may see and not understand, innervating more and more realizations.
The basic emotions we can obtain from facial movements are;
Happiness
Sadness
Surprise
Fear
Anger
Disgust
Contempt
Check out this slide below and see if can pick out what these expressions are. Keep in mind that they would normally be happening at 500ms to 250ms.