There has always been interest in certain phases and aspects of history - military history is a perennial bestseller, the Civil War, that sort of thing. But I think that there is a lot of interest in historical biography and what's generally called narrative history: history as story-telling.
The president of the United States from the 1940s until 2017 was considered the leader of the free world - probably the most powerful person in the world - not simply in terms of America's military might but in terms of the moral authority of the president. Donald Trump has largely abdicated that.
Harry Truman's decision to fire Douglas MacArthur at the height of the Korean War in April 1951 shocked the American political system and astonished the world. Much of the world didn't realize the president had the power to fire a five-star general; much of America didn't realize Truman had the nerve.