-~7- I hope that I have provided cnough information to dexonstrate that the risk from nuclear testing at the present rate is small. Of course, a great amount of more detailed information is available, and I shall be glad to supply it to you if you wish. No scientist contends that there is no risk. We accept risk as payment for our pleasures, our comforts, and our material progress. Here the choice seems much clearer-~the terrible risk of abandoning the defense effort which is so essential under present conditions to the survival of the Free World against the small controlled risk from weapons testing. Sincerely yours, ~~ No Ar wn /s/ W. F. Libby Department of Energy Histerian’s A's ARCHIVES