The document discusses communication and provides definitions and categories of communication. It defines communication as the exchange of information between two or more people and discusses various types of communication including verbal, non-verbal, written, and visual. It also outlines key characteristics of communication such as the need for at least two people, the exchange of ideas, mutual understanding, and being an ongoing process. The document then discusses models of the communication process and potential barriers to effective communication such as semantic, psychological, organizational, and personal barriers.