When he first took the national stage, with his electrifying keynote address at the Democratic National Convention in the summer of 2004, Barack Obama, then an Illinois state senator, briefly summarized his unusual life story, with its biracial themes and trans-continental setting. "I stand here knowing that my story is part of the larger American story," he said, adding: "In no other country on earth is my story even possible."

That story, of course, would become even more astonishing, and profoundly American, four years later, when its teller would be elected president of the United States. But the first time Obama related his life story -- and in the greatest detail -- was with the publication of his 1995 memoir, Dreams From My Father: A Story of Race and Inheritance.

The book, which won wide critical acclaim and rose to No. 1 on the New York Times bestseller list, recounted the complex tale that is by now familiar to most Americans: the young Obama's racial confusion as the son of a white mother from Kansas and a dark-skinned, absentee father from Kenya; his mother's remarriage to, and eventual split from, the boy's Indonesian stepfather, with a spell in a Muslim school in Jakarta; the boy's rearing by white grandparents in Hawaii, who sent him to a private school there; his journeys through Occidental College and Columbia University, marked by a shifting intellectual worldview and numerous romances, some of them inter-racial; his path-breaking stint as the first black editor of the Harvard Law Review; and his exploits as a community organizer and Chicago lawyer with a deepening interest in politics.

In the introduction, Obama openly admitted changing some people's names and compressing both characters and chronology, mostly for the sake of narrative flow. Over the years, the president’s biographers have made inroads piecing together which characters were based on which real-life individuals, and which events were compressed or conflated.

That process has now reached a kind of zenith, with the publication last month of Barack Obama: The Story, a deeply researched, 600-page study of the president's ancestry and early life by Pulitzer Prize-winning historian and Washington Post editor David Maraniss. The result reflects the hyper-scrutiny that attaches to our chief executives. It also offers a window into how much of the life story of this self-made man may have been made up.

By some counts, The Story presents more than three-dozen instances of material discrepancy where Dreams fails to align with the facts as Maraniss reports them. Case in point: Maraniss confirmed that Mr. Obama's mother, Ann Dunham, left his father, Barack Obama, Sr., a volatile bigamist, and not the other way around, as related in Dreams.

Dreams also related the tale of Obama's paternal grandfather, Hussein Onyango, who was said to have been detained and tortured in a prison outside Nairobi for six months because of his brave defiance of British colonialists. But after a half-dozen interviews and other research, Maraniss deemed the tale "unlikely."

Maraniss did not respond to several calls requesting an interview, but Fox News caught up with him outside a Washington book signing.  "I think there's a difference between a memoir and the serious, rigorous factual history of a biography," he said. "Some of what he did was the result of mythologies that were passed along from his family, and some were for the purposes of advancing themes in his book which had more to do with finding his racial identity."