Atomic Energy for Military Purposes

The Official Report on the Development of the Atomic Bomb Under the Auspices of the United States Government

By Henry De Wolf Smyth


Chapter I. Introduction
Chapter II. Statement Of The Problem
Chapter III. Administrative History Up To December 1941
Chapter IV. Progress Up To December 1941
Chapter V. Administrative History 1942-1945
Chapter VI. The Metallurgical Project At Chicago In 1942
Chapter VII. The Plutonium Production Problem As Of February 1943
Chapter VIII. The Plutonium Problem, January 1943 To June 1945
Chapter IX. General Discussion Of The Separation Of Isotopes
Chapter X.The Separation Of The Uranium Isotopes By Gaseous Diffusion
Chapter XI.Electromagnetic Separation Of Uranium Isotopes
Chapter XII.The Work On The Atomic Bomb
Chapter XIII.General Summary
Appendix 1. Methods Of Observing Fast Particles From Nuclear Reactions
Appendix 3. Delayed Neutrons From Uranium Fission
Appendix 4. The First Self-Sustaining Chain Reaction Pile


The ultimate responsibility for our nation's policy rests on its citizens and they can discharge such responsibilities wisely only if they are informed. The average citizen cannot be expected to understand clearly how an atomic bomb is constructed or how it works but there is in this country a substantial group of engineers and scienntists who can understand such things and who can explain thei potentialities of atomic bombs to their fellow citizens. The present report is written for this professional group and is a matter-of-fact, general account of work in the USA since 1939 aimed at the production of such bombs. It is neither a documented official history nor a technical treatise for experts. Secrecy requirements have affected both the detailed content and general emphasis so that many interesting developments have been omitted.

References to British and Canadian work are not intended to be complete since this is written from the point of view of the activities in this country.

The writer hopes that this account is substantially accurate, thanks to co-operation from all groups in the project; he takes full responsibility for all such errors that may occur.

Henry DeWolf Smyth,

1st July, 1945.