Who is Harry Truman from the nonfiction book, Killing the Rising Sun?

The authors quote reporters who describe Truman, the thirty-third president of the United States, as “cool” and “matter-of-fact” in Chapter 26 because this fits their overall image of him. Truman is portrayed as a resolute leader unruffled by his circumstances, even if he is angered by Japan’s delayed replies to his surrender demands, and even if he is forced into marathon haggling sessions with Joseph Stalin, a communist tyrant he clearly distrusts and dislikes. This decisive, collected nature explains Truman’s willingness to drop the new atomic weapons on Japan, thus saving, in the authors’ view, up to 1 million American lives and securing a reformed, reconstructed Japanese ally to help fight communism later.