Einstein letter

Albert Einstein's typed signed letter to President Roosevelt, 1939, with penciled note by Leo Szilard at top "Original, not sent!"
Einstein’s Nuclear Warning Letter to President Roosevelt to Auction with $4m – $6m Estimate
An unsent version of the 1939 letter from Albert Einstein to President Franklin Roosevelt warning that Germany could be assembling nuclear weaponry comes to auction on September 10 at
Swann Galleries’ Top Autographs Sale of All Time Led by Mozart and Einstein