The document discusses communication and defines it as a process where people share meanings via symbolic messages. It presents Shannon and Weaver's model of communication as well as two additional models that involve a sender, encoder, message, channel, receiver, decoder, and feedback. The document also lists several functions of communication such as informing, commanding, influencing, and integrating. Finally, it discusses principles of effective communication such as clarity, adequacy, timing, integrity, empathy, credibility, and listening.