"A Mathematical Theory of Communication" is an article by mathematician Claude Shannon published in Bell System Technical Journal in 1948. It was renamed The Mathematical Theory of Communication in the 1949 book of the same name, a small but significant title change after realizing the generality of this work. It has tens of thousands of citations, being one of the most influential and cited scientific papers of all time, as it gave rise to the field of information theory, with Scientific American referring to the paper as the "Magna Carta of the Information Age", while the electrical engineer Robert G. Gallager called the paper a "blueprint for the digital era". Historian James Gleick rated the paper as the most important development of 1948, placing the transistor second in the same time period, with Gleick emphasizing that the paper by Shannon was "even more profound and more fundamental" than the transistor.
It is also noted that "as did relativity and quantum theory, information theory radically changed the way scientists look at the universe". The paper also formally introduced the term "bit" and serves as its theoretical foundation.
