1. Physical principles involved in transistor action. 2. The theory of p-n junctions in semiconductors and p-n junction transistors. 3. Communication theory of secrecy systems

First Comprehensive Report on the Transistor, with Shannon's Foundation of Modern Cryptography

(1) Bardeen, John (1908-91) and Brattain, Walter (1902-87). Physical principles involved in transistor action. In Bell System Technical Journal 28, no. 2 (April 1949): 239-77. (2) Shockley, William (1910-89). The theory of p-n junctions in semiconductors and p-n junction transistors. In ibid.: 435-89. (3) Shannon, Claude (1916-2001). Communication theory of secrecy systems. In ibid.: 656-715. Whole volume. iv, 753, [1], v-viii pp. Illustrated. 221 x 148 mm. Library buckram. Very good. Library stamps and label on endpapers.

(1) First Editions. No. (1), Bardeen and Brattain's paper, is the first comprehensive report on the point-contact transistor, created in December 1947 and announced in three brief papers published in the Physical Review in 1948. The transistor gradually replaced the bulkier vacuum tube, allowing heat reduction and miniaturization of electronic devices. Transistors began to be employed on a large scale in computer manufacturing in the late 1950s; they were eventually miniaturized and incorporated into microprocessors.

Bardeen and Brattain shared the 1956 Nobel Prize for physics with William Shockley (see below) for their investigations of semiconductors (the materials of which transistors are made) and for their discovery of the transistor. Origins of Cyberspace 450.

No. (2) is a detailed account of the junction transistor invented by Shockley shortly after Bardeen and Brattain's invention of the point-contact transistor. Shockley's design marked a substantial improvement over the point-contact transistor, whose "delicate mechanical configuration would be difficult to manufacture in high volume with sufficient reliability" (Computer History Museum, "The silicon engine: A timeline of semiconductors in computers" [internet reference]). Shockley disagreed with Bardeen and Brattain's explanation of how the transistor worked, claiming that "positively charged holes could also penetrate through the bulk germanium material-not only trickle along a surface layer. Called 'minority carrier injection,' this phenomenon was crucial to operation of his junction transistor, a three-layer sandwich of n-type and p-type semiconductors separated by p-n junctions. This is how all 'bipolar' junction transistors work today" (ibid.). Bell Laboratories began manufacturing junction transistors in quantity in 1951; they dominated the market for many years. Magill, Nobel Prize Winners: Physics, pp. 675-704.

No. (3), Shannon's discussion of cryptography from the viewpoint of information theory, "is one of the foundational treatments (arguably the foundational treatment) of modern cryptography. It is also a proof that all theoretically unbreakable ciphers must have the same requirements as the one-time pad [a secret random key used only once]" (Wikipedia). Shannon published an earlier version of his cryptography research in the classified report A Mathematical Theory of Cryptography (Memorandum MM 45-110-02, Bell Laboratories, Sept. 1, 1945). Shannon, Collected Papers, no. 25.