## A Symbolic Analysis of Relay and Switching Circuits. Offprint from: Transactions of the American Institute of Electrical Engineers, vol. 57.

New York: American Institute of Electrical Engineers [AIEE], 1938.

**First edition, incredibly rare separately-paginated offprint**, **one of four known copies**, of Shannon’s famous MIT Master’s Thesis, which Herman Goldstein has called “masterful … surely one of the most important master’s theses ever written … a landmark in that it helped to change digital circuit design from an art to a science” (*The Computer From Pascal to Von Neumann*, pp. 119-120). While working on his thesis, Shannon was invited to present his work at the Summer Conference of the AIEE, June 2-24, 1938. His presentation was published in December 1938 in the AIEE *Transactions*; the present offprint of that article is dated 16 September 1938. “Claude Shannon, in his master’s thesis entitled ‘A Symbolic Analysis of Relay and Switching Circuits,’ submitted to MIT on August 10, 1937, showed that the two-valued algebra developed by George Boole could be used as a basis for the design of electrical circuits … This thesis became the theoretical basis for the electronics and computer industries that were developed after World War II” (historyofinformation.com). “In 1936 [Shannon] accepted the position of research assistant in the Department of Electrical Engineering at the Massachusetts Institute of Technology. The position allowed him to continue studying toward advanced degrees while working part-time for the department. The work in question was ideally suited to his interests and talents. It involved the operation of the Bush differential analyzer, the most advanced calculating machine of that era … Also of interest was a complex relay circuit associated with the differential analyzer that controlled its operation and involved over one hundred relays. In studying and servicing this circuit, Shannon became interested in the theory and design of relay and switching circuits. He had studied symbolic logic and Boolean algebra at Michigan in mathematics courses, and realized that this was the appropriate mathematics for studying such two-valued systems. He developed these ideas during the summer of 1937, which he spent at Bell Telephone Laboratories in New York City, and, back at MIT, in his master’s thesis, where he showed how Boolean algebra could be used in the analysis and synthesis of switching and computer circuits. The thesis, his first published paper, aroused considerable interest when it appeared in 1938 in the AIEE *Transactions*. In 1940 it was awarded the Alfred Noble Prize of the combined engineering societies of the United States” (*Collected Papers*, pp. xi-xii). “In his paper, Shannon proved that Boolean algebra and binary arithmetic could be used to simplify the arrangement of the electromechanical relays then used in telephone routing switches, then turned the concept upside down and also proved that it should be possible to use arrangements of relays to solve Boolean algebra problems. Exploiting this property of electrical switches to do logic is the basic concept that underlies all electronic digital computers. Shannon's work became the foundation of practical digital circuit design when it became widely known among the electrical engineering community during and after WW2. The theoretical rigor of Shannon’s work completely replaced the *ad hoc* methods that had previously prevailed” (history-computer.com/ModernComputer/thinkers/Shannon.html). This copy of the offprint is from Shannon’s personal files – we are not aware of any copy originating from any other source. Not on OCLC, no copies in auction records.

*Provenance*: The personal files of Claude E. Shannon (unmarked).

“Shannon (1916-2001), who died in February after a long illness, was one of the greatest of the giants who created the information age. John von Neumann, Alan Turing and many other visionaries gave us computers that could process information. But it was Claude Shannon who gave us the modern concept of information – an intellectual leap that earns him a place on whatever high-tech equivalent of Mount Rushmore is one day established …

“And that’s not even counting the master’s dissertation Shannon had written 10 years earlier – the one where he articulated the principles behind all modern computers. ‘Claude did so much in enabling modern technology that it’s hard to know where to start and end,’ says [Robert] Gallager, who worked with Shannon in the 1960s. ‘He had this amazing clarity of vision. Einstein had it, too – this ability to take on a complicated problem and find the right way to look at it, so that things become very simple.’

“For Shannon, it was all just another way to have fun. ‘Claude loved to laugh, and to dream up things that were offbeat,’ says retired Bell Labs mathematician David Slepian, who was a collaborator of Shannon’s in the 1950s. Shannon went at math like a stage magician practicing his sleight of hand: ‘He would circle around and attack the problem from a direction you never would have thought of,’ says Slepian – only to astonish you with an answer that had been right in front of your face all the time. But then, Shannon also had a large repertoire of real card tricks. He taught himself to ride a unicycle and became famous for riding it down the Bell Labs hallways at night-while juggling. (‘He had been a gymnast in college, so he was better at it than you might have thought,’ says his wife Betty, who gave him the cycle as a Christmas present in 1949.)

“At home, Shannon spent his spare time building all manner of bizarre machines. There was the Throbac (THrifty ROman-numerical BAckward-looking Computer), a calculator that did arithmetic with Roman numerals. There was Theseus, a life-sized mechanical mouse that could find its way through a maze. And perhaps most famously, there was the ‘Ultimate Machine’ – a box with a large switch on the side. Turn the switch on, and the lid would slowly rise, revealing a mechanical hand that would reach down, turn the switch off, and withdraw – leaving the box just as it was.

“‘I was always interested in building things with funny motions,’ Shannon explained in a 1987 interview with *Omni *magazine (one of the few times he spoke about his life publicly). In his northern Michigan hometown of Gaylord, he recalled, he spent his early years putting together model planes, radio circuits, a radio-controlled model boat and even a telegraph system. And when he entered the University of Michigan in 1932, he had no hesitation about majoring in electrical engineering.

“After graduating in 1936, Shannon went directly to MIT to take up a work-study position he had seen advertised on a postcard tacked to a campus bulletin board. He was to spend half his time pursuing a master’s degree in electrical engineering and the other half working as a laboratory assistant for computer pioneer Vannevar Bush, MIT’s vice president and dean of engineering. Bush gave Shannon responsibility for the Differential Analyzer, an elaborate system of gears, pulleys and rods that took up most of a large room – and that was arguably the mightiest computing machine on the planet at the time.

“Conceived by Bush and his students in the late 1920s, and completed in 1931, the Differential Analyzer was an analog computer. It didn’t represent mathematical variables with ones and zeroes, as digital computers do, but by a continuous range of values: the physical rotation of the rods. Shannon’s job was to help visiting scientists ‘program’ their problems on the analyzer by rearranging the mechanical linkages between the rods so that their motions would correspond to the appropriate mathematical equations.

“Shannon couldn’t have asked for a job more suited to his love of funny motions. He was especially drawn to the analyzer’s wonderfully complicated control circuit, which consisted of about a hundred ‘relays’ – switches that could be automatically opened and closed by an electromagnet. But what particularly intrigued him was how closely the relays’ operation resembled the workings of symbolic logic, a subject he had just studied during his senior year at Michigan. Each switch was either closed or open – a choice that corresponded exactly to the binary choice in logic, where a statement was either true or false. Moreover, Shannon quickly realized that switches combined in circuits could carry out standard operations of symbolic logic. The analogy apparently had never been recognized before. So Shannon made it the subject of his master’s thesis, and spent most of 1937 working out the implications. He later told an interviewer that he ‘had more fun doing that than anything else in my life.’

“Certainly his dissertation, ‘A Symbolic Analysis of Relay and Switching Circuits,’ makes for a compelling read – especially given what’s happened in the 60-plus years since it was written. As an aside toward the end, for example, Shannon pointed out that the logical values true and false could equally well be denoted by the numerical digits 1 and 0. This realization meant that the relays could perform the then arcane operations of binary arithmetic. Thus, Shannon wrote, ‘it is possible to perform complex mathematical operations by means of relay circuits.’ As an illustration, Shannon showed the design of a circuit that could add binary numbers.

“Even more importantly, Shannon realized that such a circuit could also make comparisons. He saw the possibility of a device that could take alternative courses of action according to circumstances – as in, ‘if the number X equals the number Y, then do operation A.’ Shannon gave a simple illustration of this possibility in his thesis by showing how relay switches could be arranged to produce a lock that opened if and only if a series of buttons was pressed in the proper order.

“The implications were profound: a switching circuit could decide – an ability that had once seemed unique to living beings. In the years to come, the prospect of decision-making machines would inspire the whole field of artificial intelligence, the attempt to model human thought via computer. And perhaps by no coincidence, that field would fascinate Claude Shannon for the rest of his life.

“From a more immediate standpoint, though, a switching circuit’s ability to decide was what would make the digital computers that emerged after World War II something fundamentally new. It wasn’t their mathematical abilities *per se* that contemporaries found so startling (although the machines were certainly very fast); even in the 1940s, the world was full of electromechanical desktop calculators that could do simple additions and subtractions. The astonishing part was the new computers’ ability to operate under the control of an internal program, deciding among various alternatives and executing complex sequences of commands on their own.

“All of which is why ‘A Symbolic Analysis of Relay and Switching Circuits,’ published in 1938, has been called the most important master’s thesis of the 20th century. In his early 20s, Claude Shannon had had the insight crucial for organizing the internal operations of a modern computer – almost a decade before such computers even existed. In the intervening years, switching technology has progressed from electromechanical relays to microscopic transistors etched on silicon. But to this day, microchip designers still talk and think in terms of their chips’ internal ‘logic’ – a concept borne largely of Shannon’s work” (‘Claude Shannon: reluctant father of the digital age,’ *MIT Technology Review*, July 1, 2001).

“Claude Elwood Shannon was born in Petoskey, Michigan, on Sunday, April 30, 1916 … The first sixteen years of Shannon’s life were spent in Gaylord, where he attended the Public School, graduating from Gaylord High School in 1932. As a boy, Shannon showed an inclination toward things mechanical. His best subjects in school were science and mathematics, and at home he constructed such devices as model planes, a radio-controlled model boat and a telegraph system to a friend’s house half a mile away. The telegraph made opportunistic use of two barbed wires around a nearby pasture. He earned spending money from a paper route and delivering telegrams, as well as repairing radios for a local department store. His childhood hero was Edison, who he later learned was a distant cousin … In 1932 he entered the University of Michigan, following his sister Catherine, who had just received a master’s degree in mathematics there. While a senior, he was elected a member of Phi Kappa Phi and an associate member of Sigma Xi. In 1936 he obtained the degrees of Bachelor of Science in Electrical Engineering and Bachelor of Science in Mathematics. This dual interest in mathematics and engineering continued throughout his career” (*Collected Papers*, p. xi).

“After graduating from the University of Michigan in 1936 with bachelor’s degrees in mathematics and electrical engineering, Shannon obtained a research assistant’s position at the Massachusetts Institute of Technology (MIT). There, among other duties, he worked with the noted researcher Vannevar Bush, helping to set up differential equations on Bush’s differential analyzer. A summer internship at American Telephone and Telegraph’s Bell Laboratories in New York City in 1937 inspired much of Shannon’s subsequent research interests. In 1940 he earned both a master’s degree in electrical engineering and a Ph.D. in mathematics from MIT. He joined the mathematics department at Bell Labs in 1941, where he first contributed to work on antiaircraft missile control systems. He remained affiliated with Bell Labs until 1972. Shannon became a visiting professor at MIT in 1956, a permanent member of the faculty in 1958, and professor emeritus in 1978” (Britannica).

The original mark-up copy of Shannon’s MIT Master’s Thesis is dated 1937 (the MIT archived copy is dated 1940). While working on his thesis, Shannon was invited to present his work at the Summer Conference of the American Institute of Electrical Engineers, June 2-24, 1938. For this purpose, Shannon substantially rewrote his thesis, resulting in an article with the same title as the thesis. An ‘Advance Copy’ of this article was released as a preprint in June 1938 (only two known copies), and then as an official offprint on 16 September 1938, as here. The first publicly available publication was in the publisher’s cloth-bound volume of the *Transactions* (Vol. 57 (1938), pp. 713-23), and in a year-end Supplement (December 1938) issued in printed wrappers.

4to (279 x 217mm), pp. [1], 2-11, [1]. Stapled self-wrappers (tiny brown spot in inner margin of first four pages, hand-applied ink-stamp to upper left of front wrapper ‘A Reprint from the Dept. of Electrical Engineering 141 Mass. Institute of Technology’ partially covering title and author). Near Fine.

Item #5553

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Price:
$150,000.00
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