curity. For reasons of security a few results have been 

 omitted. These few are mainly technical correlations, 

 as between exact distance and damage, or exact dis- 

 tance and pressure. Good public relations and the duty 

 of the Services to the public demand that the fullest 

 account possible be made available. 



The facts included should help the public form 

 sound conclusions and participate in the planning of 

 national and international policies. Bulk release of 

 energy from the nucleus is new on the earth ; its por- 

 tent is unlimited. But if it — and we — are to survive, 

 it must be controlled. And adequate control cannot be 

 achieved unless the people know the facts. 



The present official account was written by the same 

 group which prepared the over-all top-secret report 

 recently transmitted by Vice Admiral W. H. P. Blandy, 

 Commander of Joint Task Force One, to the Joint 

 Chiefs of Staff. 



To the many persons who helped in the prepara- 

 tion of this Report, I extend my thanks. I am partic- 

 ularly indebted to Mr. David Z. Beckler, Deputy His- 

 torian, and Mrs. Virginia Shapley, Editor. 



W. A. Shurcliff, 

 Historian, Joint Task Force One 



February 7, 1947 



IV 



