# Claude Shannon

**Claude Shannon** (1916-2001) was a theoretical mathematician and electrical engineer who is regarded as "the father of information theory". In a creative burst beginning in 1938 and lasting for at least a dozen years, Shannon published a half dozen seminal papers that created a revolution in mathematics, communications, computer engineering, cryptography, and information science. Shannon's effect on the world arguably can be considered to be at least as great as that of Einstein, who is so much more widely known. During his career, Shannon studied at M.I.T., worked for a time at Bell Laboratories, and later returned to M.I.T. as a professor.

Recognized as a premier voice in the engineering community from the 1940's onward, Shannon had become a figure of some public and popular acclaim by the time of his retirement. An enormous number of resources exist about him on the web. In his twilight years, Shannon suffered from Alzheimer's disease.

## Switching algebra

Shannon made a critical step enabling hardware design of a computer in his 1938 MIT master's thesis, "A symbolic analysis of relay and switching circuits"^{[1]}, in which he associated boolean algebra, a kind of mathematical system that had been known for centuries, with the design of logic gates in digital hardware. Shannon called boolean algebra "switching algebra" in the context of digital hardware design.

## Information Theory

The field of information theory was launched in 1948 by Shannon's ground-breaking, two-part paper "A Mathematical Theory of Communication"^{[2]}.
It was shortly followed by a book of the same name (ISBN 978-0-252-09803-1) which has since been reprinted many times. Information theory is devoted to messages and signals using techniques drawn from mathematical probability, and linking discrete and continuous mathematics in ways that later turned out to be helpful, not just in the fields of communications and computers, but also on thinking about biological processes and linguistics. He was also a pioneer in developing methods for computers to play chess.

## Cryptography

During World War II, Shannon performed classified research for the U. S. government on cryptography. His "Communication Theory of Secrecy Systems" (1949)^{[3]} became the seminal paper for cryptography as an academic discipline, and was later joined by his work on cryptography "A Mathematical Theory of Cryptography" (1945)^{[4]}, which had been classified during the war.

## Publications

This list is not at all complete, but it includes Shannon's most of his early and highly influential works. Papers are shown in order of appearance:

- "A symbolic analysis of relay and switching circuits" (1938) - master's thesis in EE at MIT
^{[1]}*This linked Boolean algebra to the design of digital circuits (and called it "Switching Algebra")*

- "A Mathematical Theory of Cryptography" (1945) - Bell Laboratories Memorandum MM 45-110-02. Classified at the time of its publication
^{[4]}. - "A mathematical theory of communication" (1948) - published in two parts in Bell System Technical Journal: July, vol. 27, pp. 379-423, and Oct., vol. 28, pp. 623-656.
^{[2]}*This paper coined the use of the word "bit" and had important implications about the maximum amount of information that could be shoved into a given amount of spectrum before being overwhelmed by noise, a fundamental limit that became known as Shannon's Law. It would be 45 years before the scientific world was able to verify all the predictions in this paper.*

- "Communication Theory of Secrecy Systems (1949), Bell System Technical Journal, vol. 28, pp. 656-715, 1949
^{[3]}. - "Communication In The Presence Of Noise (1949), Proceedings of the Institute of Radio Engineers (IRE), vol. 37, pp. 10–21, Jan. 1949
^{[5]}.*This paper extends and elaborates on "A Mathematical Theory of Communication". It was reprinted in Proceedings of the IEEE in 1984 and again in 1998.*

- "Probability of error for optimal codes in a Gaussian channel" (1959) originally in Bell Systems Technical Journal, vol. 38, pp. 611–656, 1959
^{[6]}.

## Other statue instances

An instance of Eugene Daub's life-sized sculture of Shannon stands at the entrance to Bell Laboratories (subsequently part of Alcatel-Lucent) in Murray Hill, NJ. Visitors regularly photograph it, often with themselves standing beside it.

## References

- ↑
^{1.0}^{1.1}A symbolic analysis of relay and switching circuits, downloadable at MIT; DOI 10.1109/T-AIEE.1938.5057767 - ↑
^{2.0}^{2.1}A mathematical theory of communication, downloadable at Wiley; DOI 10.1002/j.1538-7305.1948.tb01338.x - ↑
^{3.0}^{3.1}Communication theory of secrecy systems, downloadable at typeset.io; DOI j.1538-7305.1949.tb00928.x - ↑
^{4.0}^{4.1}Shannon, C.E. (1945) A Mathematical Theory of Cryptography. Bell System Technical Memo MM 45-110-02, September 1, downloadable at Evervault. - ↑ Communication In The Presence Of Noise, downloadable at MIT; DOI 10.1109/JRPROC.1949.232969
- ↑ Probability of error for optimal codes in a Gaussian channel, downloadable at Wiley; DOI j.1538-7305.1959.tb03905.x