This chapter examines communication as a multifaceted, cognitive, social, and purposeful activity. It is described as process that can profoundly influence cognition, emotion and behavior, acting as coding system to the brain. The chapter emphasizes that meaning depends on shared knowledge and inferring intentions by introducing the fundamental Shannon and Weaver model (sender, receiver, channel, message, noise) and expanding it through Jakobson's six communication functions (emotive, poetic, phatic, metalinguistic, referential, and conative). One focus is on Grice’s Cooperative Principle and the concept of Implicature, the inferential mechanism that allows one to fill the gap between what is said and what is meant when conversational rules are violated. The Psychology of communication is then deepen starting by the pragmatic of communication by Watzlawick et al., which axioms can be thought as pragmatic rules to guide communication. In this regard, it is important to consider communication as an act, which includes both verbal and nonverbal components. The two parts (verbal and nonverbal) are equally important, and the chapter provides an extensive description of many possible ways to communicate using the body. The last part of text is then dedicated to effective communication, communication styles and persuasion, meant as an intentional process to change attitudes or behaviors. We argue that effective communication and persuasion are not about simply transmitting information, but about managing a complex, interactive, and context-dependent process where intention, nonverbal cues, coherence, and a deep understanding of the audience are paramount. Theoretical models of persuasion are described as well as some concrete application.