His biography "Truman" is the best bio I have ever read. I've read it three times, and each time I read it, it teaches me something new about politics and human nature.
"1776" and "Mornings on Horseback" are both excellent as well.
Given the time in which he was required to make critical decisions--Greece, the Marshal Plan, Iron Curtain, Berlin, NATO, Korea, MacArthur, Armed Serices Act of '47, the hydrogen bomb, Eugene McCarthy and the myriad other crises in conjuction with the on-set of the Cold War, Harry S Truman(no period, his middle name is the letter ''S'' not the first letter of a middle name), will go down in history as one of the greatest presidents.