Based on the premise that effective teaching depends on successful communication, this booklet discusses the nonverbal dimension of communication. The booklet contends that humans use nonverbal communications for the following reasons: (1) words have limitations; (2) nonverbal signals are powerful; (3) nonverbal messages are likely to be more genuine; (4) nonverbal signals can express feelings too disturbing to state; and (5) a separate communication channel is necessary to help send complex messages. The booklet argues that teachers should be aware of nonverbal communication in the classroom to become better receivers of student messages and to gain the ability to send students positive signals that reinforce learning, and at the same time become more adept at avoiding negative signals that stifle learning. Several significant research highlights are presented and various areas of nonverbal expression are treated, including facial expressions; eyes; vocal intonation; touching; body postures and movements; dress; and use of space. The conclusion of the booklet maintains that if effective communication is to be achieved in today's schools, it must be as an open process where teachers and students possess the ability to send and receive messages accurately. (A table is included, and 181 references are appended.) (MS)