This book could have been written in two ways: downward, or upward. A book like this is written downward when it’s the work of an expert, straining to send a decipherable message to the rest of us without dumbing down, struggling to remember what it must have been like to be a novice. A book like this is written upward when it’s the work of learners, struggling to communicate what they are learning, as part of the very process of learning it. Books of the first kind come from the satisfaction of already knowing. Books of the second kind come from what physicist and bon vivant Richard Feynman called the pleasure of finding things out.

Each model has its attractions and its failings, but this has been a book of the second kind, a book written upward. We are biographers, not mathematicians or physicists or engineers. The best we can say for this inexpert book of ours is that we’ve tried to write as we’d like to live. That is, we began with a nagging sense that there is something harmful in using without understanding, or at least trying to understand. We began with the idea that there is something ungrateful and grasping in enjoying our bounty of information without bothering to understand how it got here.

We are not the first to live with that sense, nor to try to remedy it. Here is how Arthur Koestler, a physics student turned novelist, once put it:

We would add: it is not the Internet that is unnatural, nor our feast of information, but a refusal to consider what their origins are, how and why they are here, where they sit in the flow of our history, and what kinds of men and women brought them about. We think there is something of an obligation in beginning to learn these things. We think that the honor our subject would have cared about—if he cared at all—would not have been adulation, but a bit of comprehension.

We’ve had great help in fulfilling this obligation. Dan Kimerling is a friend and entrepreneur—and someone who, no doubt, Shannon would have admired. He first suggested the idea of a biography of Claude Shannon. It may have been the casual remark of a friend (accompanied by a book about Bell Labs), but it has led to the work you hold in your hands. So for that inspiration, we are grateful to Dan.

For believing in us from the start and for seeing the value in this project when it was simply an idea in our minds, we are indebted to Laura Yorke, our agent. She encouraged us to pitch only the faintest of ideas to none other than Alice Mayhew and prodded us at the right times to bring this book to pass. She is a legend in the book business and deservedly so!

Jon Gertner, author of The Idea Factory, inspired this project unknowingly and then collaborated on it generously. He responded to queries consequential and not, offered contacts and research, and shared an unpublished oral history of Thornton Fry and the Bell Labs mathematics group that proved critically useful. He was that most valuable guide for a writer of historical narrative: someone who has walked the same path before and knows where the dead ends are. He was generous enough to point them out to us, and we are deeply grateful for his kindness. (Oh, and if the reader hasn’t already read his book The Idea Factory, we strongly recommend it. There is not a better history of Bell Labs, and few better portraits of how innovative organizations come to be built.) Also invaluable to us as guides to Shannon’s life and work were James Gleick’s The Information and Erico Marui Guizzo’s master’s thesis, “The Essential Message.”

Johannah-King Slutzky proved a first-rate research assistant. Finding people outside of the worlds of science and engineering who know Shannon’s name is difficult; finding someone like Johannah—who had written her own piece about Shannon before she started working on this project—was a real stroke of luck. She was diligent, thoughtful, and as excited about the research as we were.

Professor Sergio Verdú, of Princeton University, was an indispensable guide to the world of information theory and brought his collegiality and thoughtfulness to our every interaction. His enthusiasm for the arcana of Shannon’s life kept us motivated throughout the project, and he devotedly read every page and fixed many errors. As we write this, he and filmmaker Mark Levinson (of Particle Fever fame) are at work on a documentary on Shannon. We have no doubt that it will be marvelous.

We connected with Dr. Alex Magoun late in the life cycle of this project—but boy, are we glad we did! He provided his own copyedit and corrected many errors in the draft. That he read with both an enthusiast’s eye for the subject and a trained historian’s sense for where we might have erred helped us immeasurably. We are grateful for the many hours he spent and the many mistakes he caught.

Will Goodman, Internet sleuth extraordinaire, aided us in tracking down the contact information of various Shannon family members and contemporaries. We like to think Shannon himself might have been impressed by Will’s roving curiosity—he’s a twenty-first-century tinkerer-detective if ever there was one.

To the Shannon family, we thank you for taking the time to share family lore with two perfect strangers. Betty Shannon agreed to speak with us, a conversation that gave us a rich look at the relationship between her and her late husband. Claude’s son and daughter, Andrew and Peggy Shannon, also spoke to us at length. Both Shannons were generous enough to read a familiar story about a man they knew well and correct errors (and even typos!) along the way. We could not have completed this project without their help, and we are in their debt.

Like the Shannons, many people answered cold emails and phone calls and took the time to sit down with us and talk. Robert Gallager allowed us an interview—and then painstakingly read each page of the draft and corrected numerous missteps. He was incredibly generous with his time and with his patience for two nontechnical writers. Arthur Lewbel also read a draft, offered wise suggestions, and gave us a window into Shannon’s life as a juggler that we could not have gotten otherwise. Tom Kailath helped us make sense of Shannon and Wiener’s contributions to information theory and read an early version of the text. Dave Forney wrote a long memo about this text that proved enormously helpful and helped us lock down the mathematics as best as two nonmath minds could. We appreciate their time and contribution.

Kevin Currie helped us find, assemble, and select the photography in the middle of this book. With no prior experience doing such a thing, he jumped right in, and he did a marvelous job. Without his help, we could not have gathered the necessary photos to tell this story well—and we are grateful to him for his help.