His writings, which stretched across eight decades, helped Americans understand a president who transformed the office and shaped the postwar years.

William E. Leuchtenburg, one of the nation’s preeminent historians and the leading scholar on President Franklin D. Roosevelt and the New Deal, died Tuesday at the age of 102.

William E. Leuchtenburg, a leading scholar of Franklin Roosevelt and the Great Depression, has died at age 102.

One was a filmmaker, the other a scholarly adviser (who sometimes appeared on camera), and the two became close friends, working together for more than 40 years.

William E. Leuchtenburg, a prize-winning historian widely admired for his authoritative writings on the U.S. presidency and as the reigning scholar on Franklin Roosevelt and the New