A Symbolic Analysis of Relay and Switching Circuits (the 1938 paper)

This is the paper Claude Shannon published in 1938 from his master's thesis in electrical engineering at the Massachusetts Institute of Technology, and it opens by saying so: it is an abstract of a thesis presented at MIT for the degree of master of science. It is 27 pages in this scan, which carries no text layer, so the archive describes it from its source.

The paper takes the algebra George Boole published in the nineteenth century, in which statements are true or false and combine by a small set of rules, and applies it to the relay circuits that ran telephone exchanges. A relay is open or closed, a statement is false or true, and the same equations describe both. A designer could then write a circuit's behavior as an expression, simplify the expression, and build the smaller circuit.

Before this, relay networks were designed by hand and by experience. Shannon gave them a calculus. The typewritten thesis itself is catalogued separately in this archive.