as part of the statistical analysis of the breaking of the German second world war Enigma ciphers. The main landmark event that opened the way to the development of the information theory form of communication theory was the publication of an article by Claude Shannon (1916–2001) in the Bell System Technical Journal in July and October 1948 under the title "A Mathematical Theory of Communication". Shannon focused on the problem of how best to encode the information that a sender wants to transmit. He also used tools in probability theory, developed by Norbert Wiener. They marked the nascent stages of applied communication theory at that time. Shannon developed information entropy as a measure for the uncertainty in a message while essentially inventing the field of information theory. "The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point." In 1949, in a declassified version of Shannon's wartime work on the mathematical theory of cryptography ("Communication Theory of Secrecy Systems"), he proved that all theoretically unbreakable ciphers must have the same requirements as the one-time pad. He is also credited with the introduction of sampling theory, which is concerned with representing a continuous-time signal from a (uniform) discrete set of samples. This theory was essential in enabling telecommunications to move from analog to digital transmissions systems in the 1960s and later. In 1951, Shannon made his fundamental contribution to natural language processing and computational linguistics with his article "Prediction and Entropy of Printed English" (1951), providing a clear quantifiable link between cultural practice and probabilistic cognition. Interpersonal Communication Theories in interpersonal communication are concerned with the ways in which very small groups of people communicate with one another. It also provides the framework in which we view the world around us. Although interpersonal communication theories have their origin in mass communication studies of attitude and response to messages, since the 1970s, interpersonal communication theories have taken on a distinctly personal focus. Interpersonal theories examine relationships and their development, non-verbal communication, how we adapt to one another during conversation, how we develop the messages we seek to convey, and how deception works. Organizational Communication Organizational communication theories address not only the ways in which people use communication in organizations, but also how they use communication to constitute that organization, developing structures, relationships, and practices to achieve their goals. Although early organization