Communication theory is the study of how information is transmitted and understood between individuals or groups. It explores the processes involved in sending and receiving messages, including the roles of the sender, receiver, and the medium used. Key concepts include encoding, decoding, feedback, and noise, which can affect the clarity of communication. Various models, such as the Shannon-Weaver model and Berlo's SMCR model, help illustrate these processes. Communication theory also examines different contexts, including interpersonal, group, and mass communication, to understand how cultural, social, and psychological factors influence the way messages are conveyed and interpreted.