[rcocean]

Thanks for posting the letter. Per "The making of the A-bomb":

"He (Szilard) told Einstein of about the experiments and his calculations toward a chain reaction in uranium and graphite. Long afterwords he would recall with surprise that Einstein had not heard of the possibility of a chain reaction. When Szilard mentioned it, Einstein interjected, "I never thought of that".

After going to Dr. Sachs, who suggested they write FDR, Szilard prepared a draft letter to Roosevelt. The letter was in German because Einstein was insecure about his English.

Einstein, Slizard and Sachs then rewrote, revised, and translated the letters into English. They drafted two versions, Einstein signed both and returned them to Sachs and Slizard.

Slizard choose 1 letter, and wanted Charles Lindberg to deliver it to FDR. However, since Lindberg was unavailable, Sachs delivered the letter to FDR.

[GSlob]

Given that no love was lost between Charles Lindbergh and FDR, this part of the story is less than plausible.