Einstein's 1939 Letter to President Franklin D. Roosevelt
A pivotal moment in history where Einstein's scientific concerns influenced global policy on nuclear development.
Letter: 1939
Albert Einstein to Franklin D. Roosevelt
"I have a feeling that the world may not be at peace if the atomic energy source is not controlled."
In this urgent correspondence, Einstein alerted President Roosevelt about the potential for Nazi Germany to develop atomic weapons. The letter emphasized the importance of the U.S. entering the race for atomic research, and urged action to secure nuclear resources—particularly uranium—before the Axis powers gained dominance in this field.
Written in March 1939, the 1939 letter was the first public and official recognition of the possibility of a bomb based on nuclear fission. It is now regarded as one of the most consequential letters in the 20th century due to its role in initiating the Manhattan Project and, ultimately, the end of World War II.
Though Einstein himself did not work on the Manhattan Project, he later became an advocate for nuclear disarmament and international cooperation, lamentinging the implications of the atomic age.