In April 1943, a young physicist named Robert Serber stood up before a small group of fellow scientists in a laboratory in Los Alamos, New Mexico, and, as one attendee later recalled, began to speak in "a hazy, uncertain voice" about the project on which they would all be working. "The object," he said, "is to produce a practical military weapon
in the form of a bomb in which the energy is released by a fast neutron chain reaction in one or more of the materials known to show nuclear fission." That mechanism, of course, was the atomic bomb, which a little more than two years later would be used against Japan.
In the following weeks, Serber touched on many themes, racing to an array of chalkboards to scribble complex formulas and equations. Among other things, he addressed how big a bomb would need to be in order to achieve critical mass--between 13.5 centimeters and 9 centimeters, he calculated--and what the probability of premature detonation might be. (It was, he concluded, always a danger.) At the end of the series, his lecture notes, classified as top secret, were gathered and printed for distribution to later cadres of scientists who came to work at Los Alamos. Years after the war they were declassified, and Serber, who died in May of 1997, took the opportunity to reflect on his work and the strange culture of the laboratory, adding postscripts and other commentary reproduced in the present edition.
Serber's book is an important document in the history of science, and remains one of the most accessible introductions to nuclear physics ever written. (On that note, those who worry that it is all too easy to find bomb-building instructions in the library or on the Web should rest assured: these lectures were tough for the greatest theoretical physicists of the time to follow.) It all makes for provocative reading. --Gregory McNamee
About the Author
Robert Serber is Emeritus Professor of Physics at Columbia University. Richard Rhodes, author most recently of Farm (1989) and A Hole in the World (1990), won the Pulitzer Prize and the National Book Award for The Making of the Atomic Bomb (1987), all published by Simon and Schuster.