Roosevelt hoped the library would become an important research center and attract visitors to the museum.
The museum section of the building opened June 30, 1941.
However, the onset of World War II changed Roosevelt's plans, and the official opening of the library as a research facility was deferred as the President served a third term and then was elected to a fourth term in 1944.
He visited the library often during the war to sort and classify his records and memorabilia; and from his study in the library he delivered several of his famous radio speeches or "fireside chats".

President Roosevelt paid his last visit to Hyde Park in March 1945 and died on April 12 at Warm Springs, Georgia, at the age of sixty-three.
Roosevelt hoped the library would become an important research center and attract visitors to the museum. The museum section of the building opened June 30, 1941. However, the onset of World War II changed Roosevelt's plans, and the official opening of the library as a research facility was deferred as the President served a third term and then was elected to a fourth term in 1944. He visited the library often during the war to sort and classify his records and memorabilia; and from his study in the library he delivered several of his famous radio speeches or "fireside chats".
President Roosevelt paid his last visit to Hyde Park in March 1945 and died on April 12 at Warm Springs, Georgia, at the age of sixty-three.
Franklin D. Roosevelt Presidential Library and Museum