On this day in 1945, President Harry S Truman was briefed on the United States’ efforts to build an atomic bomb. Truman had been in office for 13 days since the unexpected death of Franklin D. Roosevelt.
In this top secret memo, Henry Stimson, Secretary of War alerts the President that:
"I think that it is very important that I should have a talk with you as soon as possible on a highly secret matter."
April 24, 1945.
from the Truman Library