He would live to see “information” turn from the name of a theory to the name of an era. “The Magna Carta of the Information Age,” Scientific American would call Shannon’s 1948 paper decades later. “Without Claude’s work, the internet as we know it could not have been created,” ran a typical piece of praise. And on and on: “A major contribution to civilization.” “A universal clue to solving problems in different fields of science.” “I reread it every year, with undiminished wonder. I’m sure I get an IQ boost every time.” “I know of no greater work of genius in the annals of technological thought.”
But in 1948, the bulk of the honors were years away. At the time, the magnitude of information theory was intelligible only to a small clutch of communications engineers and mathematicians and only available in a technical journal—Bell Labs’ Bell System Technical Journal. So it says something about the power and persuasiveness of Shannon’s ideas that “A Mathematical Theory of Communication” rapidly received attention well outside the confines of the Labs and even the field of engineering, and would, in less than a decade, turn into a kind of international phenomenon—one that Shannon himself would, ironically and futilely, try to rein in.
In the months following publication of Shannon’s paper, word of a breakthrough propagated through the community of communications engineers. “While, of course, Shannon was not working in a vacuum in the 1940s, his results were so breathtakingly original that even the communication specialists of the day were at a loss to understand their significance,” writes information theorist R. J. McEliece. Yet it was clear, even then, that these results would reshape the field. Shannon’s paper quickly became the jumping-off point for several others, which, in academic terms, is the equivalent of a round of applause. By November, only a month after the second installment of Shannon’s work, two derivative papers appeared, exploring the advantages of pulse code modulation through the prism of his earlier ideas. Five other significant papers tied directly to Shannon’s work came out soon thereafter.
Thus, beginning with the small but dedicated readership of the Bell System Technical Journal, news of information theory rippled through the mathematical and engineering worlds. It piqued the interest of one reader in particular, who would become Shannon’s most important popularizer: Warren Weaver, the director of the Division of Natural Sciences at the Rockefeller Foundation, one of the principal funders of science and mathematics research in the country.
Weaver had entered Shannon’s life earlier, when, with the support of Thornton Fry and Vannevar Bush, he awarded Shannon a contract to work on fire control during the war. Now he would play an even more pivotal role in Shannon’s career, as the catalyst behind the book-length publication of “A Mathematical Theory of Communication”—a book that would do for the theory what a technical journal article could not.
The two had met in the fall of 1948 and discussed the theory. Weaver, perhaps through an excess of enthusiasm, foresaw a world in which information theory could help computers fight the Cold War and enable instantaneous rendering of Soviet documents into English. Inspired, he praised Shannon’s work with exuberance to the head of the Rockefeller Foundation, Chester Barnard. In early 1949, Weaver sent Barnard his own layman’s translation of “A Mathematical Theory of Communication.”
“Weaver became the expositor of Shannon almost by accident,” a recent history observed. By accident, indeed: Weaver’s memo might have remained another forgotten interdepartmental missive, or an unread article in a journal, had it not been for the intervention of two men: Louis Ridenour, dean of graduate studies at the University of Illinois, and Wilbur Schramm, head of the university’s Institute for Communications Research.
Ridenour had spent the early part of the twentieth century at the rich intersection of physics and geopolitics. During World War II, he worked at the renowned MIT Radiation Laboratory, commonly known as the Rad Lab. The Rad Lab began with outsize ambitions, as an effort to perfect mass-produced radar technology to defeat the German Luftwaffe’s bombing runs against the British. It also had mysterious origins. Funded by Alfred Lee Loomis, the intensely private millionaire financier, attorney, and self-taught physicist, the lab was initially bankrolled entirely by Loomis himself. It created most of the radar systems used to identify German U-boats—and its network of scientists and technicians became much of the nucleus of the Manhattan Project. As Lee DuBridge, the lab’s director, would later quip, “Radar won the war; the atom bomb ended it.” This was the world of fighting man’s physics.
Weaver met Ridenour on official business in Champaign-Urbana, Illinois, while exploring whether the Rockefeller Foundation should fund a biological sciences program at the university. He shared a copy of his rendition of Shannon’s paper with Ridenour. He, in turn, passed the draft to Schramm, another one of the University of Illinois’s brightest stars, whose Institute for Communications Research was beginning to lay the foundation of communications as a formal field of study. By some accounts the first communications scholar, Schramm established the now world-famous Iowa Writers’ Workshop, home to authors from Robert Penn Warren to Marilynne Robinson.
Communications was, in a way, an ironic choice of field for Schramm. A botched childhood tonsillectomy had left him with a severe stutter, which so embarrassed him that, honored as the valedictorian of his high school class, he opted to play the flute instead of giving a speech. Speech difficulties notwithstanding, he graduated summa cum laude and Phi Beta Kappa from Marietta College, paused at Harvard for a master’s, and completed a PhD in American literature at the University of Iowa, while undergoing treatment at a famous stammering clinic in Iowa City.
Schramm’s many academic responsibilities included overseeing the University of Illinois Press—and, encouraged by Ridenour, he saw the opportunity in a version of the “Mathematical Theory” for the general public. His motives, and Ridenour’s as well, were those of practiced institution builders. Schramm’s institute sought credibility in any form for the emerging field of “communications studies.” Ridenour knew that the University of Illinois was debating the purchase of a computer. A volume featuring Warren Weaver and Claude Shannon published by the university would be the perfect complement to the “press’s new series of lectures by computer builders—setting up both Ridenour and Schramm to accomplish their respective projects.”
Whatever the motives, the book became a reality. By the admittedly modest standards of university presses, the volume was a roaring success. Debuting in 1949, a year after the theory was made public, The Mathematical Theory of Communication sold 6,000 copies in its first four years of printing; by 1990, it had sold more than 51,000 copies, putting it among the bestselling academic books published by a university press.
The book was ultimately one part Shannon, two parts Weaver: Part I featured Shannon’s original 1948 work; Parts II and III, by Weaver, attempted to explain the theory in as close to layman’s terms as possible. The book’s organization created the unintended impression of Weaver as a key contributor to the theory’s development. Commentators and observers would, for decades, refer to the “Shannon and Weaver” theory of information or even go so far as to call Weaver a cofounder of the theory. Weaver never indulged the inaccuracies. He was quick to correct the record, telling Ridenour, “No one could recognize more keenly than I do that my own contribution is infinitesimal as compared with Shannon’s.”
In fact, the only issue Weaver had with the text was a concern that it might have exaggerated his role in information theory’s development. Because his section was really an introduction to Shannon’s work, it should have come first:
There could very easily have been a short statement (perhaps most appropriately by myself?) apologising for coming first with my very modest bit, explaining why that is sensible, and expressing the great hope that all will be thus led on to study the really serious and important part of the book.
While Weaver fretted over appearing to claim false credit, Schramm and Ridenour celebrated. The volume’s publication accomplished everything they could have hoped for. By 1952, the University of Illinois had succeeded in acquiring a digital computer, and simultaneously, it was awarded a large federal contract for the study of “communication theory.”
The publication of The Mathematical Theory of Communication stands as one of the defining moments in the history of information theory, and not only on account of its commercial success. Even the title sent an important message: in the span of a year, Shannon’s original “A Mathematical Theory of Communication” had become the definitive “The Mathematical Theory of Communication.” As electrical engineer and information theorist Robert Gallager pointed out, the subtle change in the article’s context, from one of several articles in a technical journal to centerpiece of a book, was a mark of supremacy. It stood for the scientific community’s growing recognition that Shannon’s theory stood alone.