This course text introduces communication by asking how people define it and why different definitions matter. Instead of treating one definition as universally correct, it considers their usefulness for understanding everyday exchanges and academic inquiry. Definitions emphasizing transmission, understanding, influence, and information provide starting points for examining communication as a changing process. The opening lesson compares linear, interactional, and transactional approaches. Lasswell’s questions organize communication around the speaker, message, audience, channel, and effect, while the discussion highlights the importance of feedback. The transactional account presents participants as simultaneously sending, receiving, acting, and reacting. An example contrasting a formal performance appraisal with cafeteria conversation shows how context can alter meaning. The text then examines communication as symbolic activity. Signifiers, concepts, physical referents, and the semantic triangle explain why words do not naturally correspond to objects. Shared social experience supports understanding, while differences in culture and experience can produce gaps. Further discussion asks whether communication includes private thought and whether all behavior communicates or only intentional messages qualify. The next lesson introduces paradigms as frameworks guiding assumptions, research questions, methods, and acceptable explanations. It contrasts positivistic, interpretive, and critical perspectives through their accounts of reality, knowledge, social interaction, and power. Together, these discussions connect basic communication concepts with broader approaches to studying social life.