Presidential history differs from the other disciplines of history in that from the moment a president takes office his legacy and background are under scrutiny. As soon as a president first walks through the front door of the White House, scholars, especially historians, begin to look into a president’s childhood and early career for any indication of how and why this person became President of the United States, as the massive amount of resources dedicated to Harry Truman and his presidency exemplify. Historical analysis of Harry Truman began in 1945, the year Harry Truman took office. Over the years Harry Truman has been one of the most written about and quoted presidents, despite departing from the White House with one of the lowest job approval ratings in history. As Robert Ferrell, a leading Truman historian, stated, "… the trend of opinion was down, with the nadir coming in 1951 when, as is well-known-historians always cite it–Truman received a lower popularity rating than did Richard M. Nixon on the verge of impeachment."

Harry Truman for many years has been understood as three separate legacies: Harry Truman and the coming of the Cold War which includes Truman's use of the atomic bomb and foreign policy decisions as a whole; Harry Truman the politician which includes the election of 1948 as well as Truman's handling of domestic issues; and Harry Truman the man and personality.

Harry Truman has no more controversial and polarized legacy than his decisions that led to the coming of the Cold War. The Cold War began during Harry Truman's presidency and historians have analyzed Truman's Cold War actions from two different directions: Truman's decision to drop the atomic bomb at the end of World War II and Truman's dealings in post war foreign policy.

From the moment the atomic bombs fell on Hiroshima and Nagasaki, historians have reviewed Truman's decision-making process. A very polarized argument has developed. One group argues Harry Truman decided to drop the atomic bomb because of the military recommendations offered to him at the time. In 1947, Harry Truman's Secretary of War at the end of World War II, Henry L. Stimson, published an article titled, "The Decision to Use the Atomic Bomb." Stimson explained and defended the administration's explanation on why Truman decided to use the atomic bomb. Stimson's article is important because it defined the argument that defended Truman's decision to use the atomic bomb for now sixty years.

In 1960, Herbert Feis published The Atomic Bomb and the End of World War II. Feis was the first historian to examine the military advisor theory as an explanation on why the atomic bomb was used at the end of World War II. Feis defended the administrations explanation by explaining the information available to Truman at the time and how dropping the atomic bomb was the quickest way out of the war. Feis' work is important because it was a historical review that supported the administrations explanations.As recently as 1997, D.M. Giangreco argued in the Journal of Military History that Truman's decision to use nuclear weapons at the end of World War II was based on the military projections that an invasion of Japan would have meant the death of many more people, especially American soldiers, than the use of the bombs caused. The military advisor theory has prevailed as the accepted explanation of use of the atomic bomb for nearly sixty years.

However, many of the works about Truman over the years have argued a significant revision to the Truman Administration's explanation of why the atomic bombs were used. This revision states that Harry Truman used the atomic bombs to scare the Soviet Union and consequently brought about the Cold War. The first major work that argued this revisionist interpretation was Gar Alperovitz's Atomic Diplomacy: Hiroshima and Potsdam: The Use of the Atomic Bomb and the American Confrontation with Soviet Power. Published in 1965, Atomic Diplomacy was a revisionist look at the use of the atomic bomb to end World War II. Alperovitz questioned Truman's motives behind using the bomb and was the first to second guess the popular military expediency explanation. Rather, Alperovitz argued that Truman used the bomb to make a political statement and to intimidate the Soviet Union with the power of the United States. Many recent historians who question Truman's decision to use the atomic bomb have linked that event with the coming of the Cold War.

The decisions around dropping the atomic bombs are a prime example of the controversy facing Harry Truman's foreign policy. Blamed by many for the onset of Cold War hostility, Truman's foreign policy decisions have been scrutinized more extensively than most other presidents'. The firing of General Macarthur, the Korean War, and Truman's handling of the Soviet Union filled Truman's years in office with controversy. The leading modern interpretation of Truman's foreign policy is Melvyn P. Leffler's A Preponderance of Power: National Security, the Truman Administration, and the Cold War. Leffler states that Truman the realist understood the world around him, and his administration, despite costly errors, protected America's national security against the Soviet threat. Other works look at Truman's foreign policy decisions as individual events.

As for all presidents, Harry Truman's decisions, including those regarding the atomic bomb and the coming of the Cold War, have been second guessed time and again. Harry Truman before all else in history was a politician, and much of the history surrounding him examines him as just that.

Truman noted by many as simply the man between Franklin Roosevelt and Dwight Eisenhower, governed a rapidly changing nation in a delicate time. How Truman dealt with the challenges that faced him is the subject of many of the great works in his historiography.

Frank McNaughton and Walter Hehmeyer wrote the first seriously taken biography of Harry S. Truman. Published in 1948, the focus of this work is the events surrounding Truman's first months in office, especially the reaction to Truman taking office and the many comparisons to Franklin Delano Roosevelt. Harold F. Gosnell's Truman's Crises is a political look at the presidency of Harry Truman. Gosnell does not delve into Truman's mind or his background but described the events that surrounded Truman's years in office from a political scientist's point of view.There are those that also looked at Truman's leadership style. Robert Underhill's The Truman Persuasions main theme is that even though Harry Truman lacked political eloquence, he was an effective persuader. Published in 1981, Underhill examined how Truman navigated a less than supportive Congress.

Despite the fact that Harry Truman left the White House with one of the lowest approval ratings of any President in history, Truman has become one of the most quoted and researched figures in American history. A major factor of why Truman has been such a prominent figure in history is the perception of who Harry Truman was and where he came from.

Harry Truman wrote two volumes of memoirs commenting on his life and years as president. Though important to the understanding of who Truman was and why he made his decision, any memoir is dangerous as an historical source because the author will only reveal what he wants to reveal. Truman himself stated in the preface to his first memoir, "For reasons of national security and out of consideration for some people still alive, I have omitted certain material." Another important but not scholarly work done about Harry Truman the man was the biography of Truman done by his only child, Margaret Truman Daniels.

The major work that examined Harry Truman and his personality is Merle Miller's Plain Speaking.Published in 1972, Plain Speaking is an oral biography of Harry S. Truman. Miller interviewed Truman in the early sixties in preparation for a planned documentary series about the former president. The documentary series never developed but in the early seventies Miller decided to use his numerous interviews to produce a book about Harry Truman. In response to the Watergate Scandal of 1972, Miller examined Truman's attitude and background using Truman as the major source to contradict the lies and corruption that Miller felt existed in Nixon's White House. Miller stated, "And as I say, during the summer of Watergate, there is a special kind of purity in what he has to say. Mary McGrory wrote some years back: 'Since Harry Truman left town almost nobody has spoken his mind. Mr. Truman took the tradition of plain speaking back to Missouri with him'". Miller showed Truman to be a honest self made man. More importantly, Miller sought to show how different Truman was from the politicians that came after him and how Truman's honesty and "plain speaking" was something sorely missed. Miller also interviewed Truman's family, friends, and those who worked around him, not to get a glimpse of the scene at the White House, but to discover who Harry Truman was.

Two other important biographies of Harry Truman are Jonathan Daniel's The Man of Independence and Alfred Steinberg's work The Man From Missouri: The Life and Times of Harry S. Truman. Jonathan Daniels served as Franklin Roosevelt's press secretary and became Truman's first press secretary upon Roosevelt's death. Published in 1950, Daniels' work focuses on Truman's childhood up until the election of 1948. Alfred Steinberg's work on Harry Truman focuses on the background of the life of Harry Truman. Published in 1962, Steinberg describes Truman's upbringing and teenage years, as well as his army life and early political career. Steinberg then delves into Truman's presidency. Steinberg's work was to be the first comprehensive look at Harry S. Truman, however shortly after Steinberg published his book, Truman's Presidential papers were released and those documents showed that many of Steinberg's conclusions were wither wrong or incomplete. Steinberg's analysis of Truman's presidency plummeted to being analytically unimportant and outdated but it remains an interesting and important look at Truman's formative years.

Steinberg was not alone in trying to make conclusions about the Truman presidency without the necessary primary resources. In the late 1970s a majority of the primary resource documents became available to researchers and the public from private and public archives. What was released in the later 1970s was ". . . one of the most informative runs-perhaps the most informative run-of manuscript records in the history of the American presidency." The release of Truman's presidential papers included confidential memoranda, un-sent letters, diary entries, and other never seen before documents written by the president's own hand. Most importantly, the Truman Presidential Library released the "Dear Bess" letters. Over the span of 49 years, Harry Truman wrote over 1000 letters to his wife, Bess Truman. These letters give the most insight to how Harry Truman viewed the world and his thoughts about current events. The release of these valuable primary resources was important to the historiography of Harry Truman because they paved the way for comprehensive and definitive works to be accomplished on the former president.

Until 1989, Truman at best had a piecemeal historiography. There were bits and pieces of Truman's legacy spread out over a wide array of disciplines. In 1989, G.K. Hall Company published The Harry S. Truman Encyclopedia. Edited by Richard S. Kirkendall, a leading Truman biographer, this work combines the work of nearly two hundred scholars and was designed to assist teachers and librarians with research. Considered a major scholarly work, The Harry S. Truman Encyclopedia was the first major attempt to combine the diverse universe of the Harry Truman legacy. However, The Harry S. Truman Encyclopedia was intended to only be used by scholars and teachers as an instructional guide. Furthermore, The Harry S. Truman Encyclopedia did not solve the problem of the piecemeal historiography of Harry Truman; it only organized the available tools to complete such a task. As Robert Ferrell stated regarding the status of works done on Harry Truman in 1990:

And yet the reader will have discerned a striking point about the place in history of Harry S. Truman as a public figure must rely on a remarkably insecure set of biographies.

Ferrell went on to say:

What this says is that the generality of historians should leave their judgment open. The definitive biography is yet to come. It may prove the book now almost in press by McCullough, or the book well along by Alonzo L. Hamby. But Truman's place in history must at least await the appearance of these books.

David McCullough's Truman was the first literary work that attempted to encompass the entire life of Harry Truman. Published in 1992, McCullough examined Truman's character and personality. However, McCullough's work answered Ferrell's call to the keyboard for a comprehensive and definitive look at Harry Truman's life. Demonized by scholarly historians as popular history, Truman is a voluminous work of over 1,100 pages. McCullough uses mostly primary resources to show how Truman thought about the world. More importantly, McCullough takes the next step in showing how Truman's personality and background influenced the decisions he made. McCullough stated, "Ambitious by nature, he was never torn by ambition, never tried to appear as something he was not. He stood for common sense, common decency. He spoke the common tongue. As much as any president since Lincoln, he brought to the highest office the language and values of the common American people."

Alonzo L. Hamby released his Man of the People in 1995. Hamby like McCullough delves into Truman's childhood and early political career to try to find out who Harry Truman was. However, Hamby does not think as fondly of Truman as McCullough does. Hamby criticizes Truman's use of the atomic bomb even though he concludes Truman did the right thing. Hamby attacks Truman's record on civil rights and Truman's domestic policy as a whole. Instead of adoring Truman's plain speaking demeanor as so many other historians have over the years, Hamby concludes Truman was doing nothing more than trying to make up for his overwhelming personal weaknesses. Hamby remarked, "The tension of becoming something he wasn't strengthened him in many ways but it also left scars: an inordinate touchiness, a quick temper, and an insatiable demand for recognition that stayed with him throughout his life." Hamby's work is also a comprehensive view of Truman's life and his presidency. Like McCullough, Hamby takes the important next of step of showing how Truman's personality and his actions as president were one in the same.

Thus lays the status of Harry Truman's legacy, and therefore, his historiography. A great rivalry now exists between scholarly historians and popular historians. Scholarly historians like Hamby argue that Truman's many weaknesses overshadowed any good that he did as president. Popular historians point to Truman as the kind of president the people should expect; a man of the people. Until Americans decide the qualifications for their leader, Truman will always be the example pointed to of the common man taking office. This is why the study of Truman is important. As long as the common man matters in American politics, Truman matters.