Smyth Report

Smyth Report

Henry DeWolf Smyth, a physicist at Princeton who worked on early stages of the atomic bomb, wrote the official public report on the Manhattan Project, popularly referred to as The Smyth Report. Issued on August 12, 1945, just three days after the second atomic bomb was dropped, the report provided the general public with an introduction to the vast engineering and production effort required for the Manhattan Project. Below is the foreword to the 1945 edition by General Leslie R. Groves followed by Smyth’s preface.

Document Type: 
Smyth Report

The story of the development of the atomic bomb by the combined efforts of many groups in the United States is a fascinating but highly technical account of an enormous enterprise. Obviously military security prevents this story from being told in full at this time. However, there is no reason why the administrative history of the Atomic Bomb Project and the basic scientific knowledge on which the several developments were based should not be available now to the general public. To this end this account by Professor H. D. Smyth is presented.

All pertinent scientific information which can be released to the public at this time without violating the needs of national security is contained in this volume. No requests for additional information should be made to private persons or organizations associated directly or indirectly with the project. Persons disclosing or securing additional information by any means whatsoever without authorization are subject to severe penalties under the Espionage Act.   

The success of the development is due to the many thousands of scientists, engineers, workmen and administrators—both civilian and military—whose prolonged labor, silent perseverance, and whole-hearted cooperation have made possible the unprecedented technical accomplishments here described. 

L. R. Groves

Major General, USA


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 scientific men who can understand such things and who can explain the 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 United States 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 cooperation from all groups in the project; he takes full responsibility for such errors as may occur.

H. D. Smyth


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