In New York lies a box of letters written by and about Barack Obama's father, revealing the hidden history of the man who would father - and then cast aside - the first black President of the USA.

And Obama will not touch them until he's stepped out of the Oval Office for the last time.

So for three years since they were found, those letters have lain in the Schomburg Center for Research in Black Culture in Harlem, their story untold - until The New York Times revealed them Saturday.

Distant relatives: Barack Obama Sr hugs ten-year-old Barack Obama Jr, in Christmas 1970. Obama Sr left the U.S. for Kenya in 1963, and hadn't seen his son since he was an infant

Troubled: Obama has spoken often of his troubled relationship with his father. That may be the reason why he will not read a collection of his father's letters that are housed in Harlem until after he leaves the White House

Discovered by archivist Christine McKay, the letters include almost two dozen written by Obama's father as well as transcripts from The University of Hawaii and Harvard, and references from friends and professors.

The letters - many typed, some written - show Barack Hussein Obama Sr as a 22-year-old Kenyan clerk frustrated with his lot in life and a craving to broaden his knowledge in the US.

Hoping to become a high-ranking economist in the Kenyan government, his persistent pursuit of financial assistance and studies took him first to the University of Hawaii and then to Harvard.

In letters from his university years, he boasts of a series of A's (and, he's disappointed to admit, B's) and marvels at the cost of living in America.

One letter from his time at the University of Hawaii - where he met Ann Dunham, Obama Jr's mother - show him delighting at the temperate climate. 'One would not know that it is winter,' he enthuses.

In another, from 1962 - one year before his son's birth, he wrote a student assistance program for help funding his Harvard studies: 'The cost of living is very high in Boston area (sic) here.

'In fact I am surprised that even a hamburger is 50 cents here, a thing I never experienced before.'

But just as telling are the absences. At no point does he mention marrying Durham, nor the birth of Barack Obama Jr on August 4, 1961.

Even in a grant application form written during his time at Harvard in 1963, he leaves a section asking about marital status and number of dependents blank.

That year he returned to Kenya with just a Masters degree and not the PhD he'd hoped for. Barack Obama Jr was just an infant. The pair would meet again just one more time, seven years on.

Travel: Barack Obama Sr - seen in family portraits in the Obama house in Kenya - moved to the US to learn economics. There he met and married Ann Dunham, Obama Jr's mother. But their relationship didn't last

'When I was ten, my father came back from Africa to visit us for Christmas,' Obama Jr. recalled in his memoir, Dreams of My Father.

'After a week of my father in the flesh, I decided that I preferred his more distant image, an image I could alter on a whim - or ignore when convenient.'

Later in the chapter, he adds: 'And yet when I reach back into my memory for the words of my father... I'm left with mostly images that appear and die off in my mind like distant sounds.

'We stand together in front of the Christmas tree and pose for pictures, the only ones I have of us together, me holding an orange basketball, his gift to me, him showing off the tie I've bought him.

'He stayed a month, then he was gone.'

Perhaps that's why the President has declined to read the letters since he was contacted three years ago.

Forgotten memories: Obama now says he has trouble remembering his father as anything more than brief images. But the letters reveal a complex and driven human being

'I thought it would be great if the president could see his father’s words,' McKay said.

But a senior White House official said that Obama, while interested, would only see the letters some time after he steps down as President next year.

When he does open the letters, he will find the story of a brilliant man who embraced America, and all its pleasures and problems - if only for a time.

'The people around here have made me feel at home,' he wrote upon arriving in Hawaii, adding that his new friends had 'called upon me to give several speeches on Africa and on Kenya.'

While at the university he excelled academically, getting an undergraduate degree in economics with honors in three years. But he also struggled badly with money - as the many requests for financial aid that make up the correspondence reveal.

'He has impressed everyone with being a genuinely enlightened twentieth-century man and the peoples of Africa should be proud to have him representing them here,' Lee E. Winters Jr, an assistant professor of English, wrote in a letter to the African-American Institute.

'Certainly I hope you will be able to renew his grant, but I hope too that you may find the wherewithal to add something to it to make a real student life for this young man possible.'

Family: Obama has reconnected with his wider family, but his father, who died in 1982, remains a mystery to him. His father had hoped to become a high-ranking Kenyan economist but began drinking as the dream faded

By 1963, however, the cracks are beginning to show. By that point his relationship to Dunham had fallen apart, and he was struggling financially.

Immigration was looking into reports that he was married in Kenya - a 'village wedding' with no documentation, he had told Dunham, according to Obama Jr's memoir - and the end was drawing near.

'Mr. Obama is not among our best students,' wrote Hendrick S. Houthakker, Harvard professor of economics, 'and his record to date leaves something to be desired.' However, he said that his 'intelligence, initiative and dilligence' boded well for him.

Obama Sr returned to Kenya and began to drink heavily as his chances of becoming the important economist he had dreamed of faded. He died in a car crash in 1982, at the age of 46.

But the documents he left behind may allow his son to understand him a little better - some day.

'The papers are rich; they tell a fascinating, traditional, self-made man’s story,' said Khalil Gibran Muhammad, the director of the Schomburg Center.

'There’s a reason to bear witness to the personal legacy that is here.'