Pre fa 



ce 



Tests A and B of Operation Crossroads, perhaps 

 the most elaborate scientific tests ever conducted, are 

 described in this official report with no attempt to 

 prove or disprove anything. Its sole purpose is to 

 present facts on the origin, planning, and execution 

 of the joint enterprise. 



The word joint needs emphasis. The Tests were 

 neither Navy tests nor Army tests; this Report is 

 neither a Navy report nor an Army report, and it has 

 not been submitted to Army or Navy for approval. 

 The Tests and the Report are the work of Joint Task 

 Force One, an agency created by the Joint (Army and 

 Navy) Chiefs of Staff and responsible only to them. 



The Report does not attempt to duplicate the capable 

 reporting of the many experienced reporters who wit- 

 nessed the Tests. Through the press the general charac- 

 ter of the Operation is known to hundreds of millions 

 of persons here and abroad. The world knows that the 

 first explosion was an atomic bomb detonation in the 

 air on July 1, 1946, sinking 5 ships, and that the second 

 explosion was an atomic bomb detonation underwater 

 on July 25, 1946, sinking 9 ships. 



But there is a wealth of information, much of it 

 technical, which has not reached the public. Time was 

 required to ferret out the significant facts; patience 

 was required to piece them together ; ingenuity was re- 

 quired to present the material without jeopardizing se- 



nt 



