Reading:
Chapter 1 "Nonverbal Communication, Basic Perspectives" from Nonverbal Communication in Human Interaction, Mark Knapp and Judith Hall, 4th Ed., Holt, Rinehart and Winston, 1997.
Recommended:
"The Repertoire of Nonverbal Behavior, Categories, Origins, Usage and Coding", Paul Ekman and Wallace Friesan, from Nonverbal Communication, Interaction and Gesture, Adam Kendon Ed., Mouton Publishers, 1981.