Joe Wrinn, Harvard University/AP Photo

Accounts of a young Barack Obama chronicled by one of his former girlfriends have shed new light on his reserved demeanor, detailing the "guardedness" of a young man searching for his identity.

In his new biography of the president, author David Maraniss publishes love letters and journal entries from Genevieve Cook, who met the 22-year-old Obama at a New York Christmas party in 1983. Excerpts published in Vanity Fair offer a new glimpse into the president's years after graduating from Columbia University.

During the course of their roughly year-long romantic relationship, Cook chronicled a man who was charming and intelligent, but also distant and emotionally unreachable.

"The sexual warmth is definitely there - but the rest of it has sharp edges and I'm finding it all unsettling and finding myself wanting to withdraw from it all," Cook wrote in her journal in February 1984. "I have to admit that I am feeling anger at him for some reason, multi-stranded reasons. His warmth can be deceptive. Tho he speaks sweet words and can be open and trusting, there is also that coolness - and I begin to have an inkling of some things about him that could get to me."

In a letter a month later, she told Obama that he has something of a "smoothed veneer" a "guardedness" that she ultimately terms "the veil."

Looking back at that period of his life, Obama admitted to Maraniss in a White House interview that he was "'deep inside my own head … in a way that in retrospect I don't think was real healthy.'"

Maraniss portrays a future president struggling with race and identity. Was the young man, raised in Hawaii and Indonesia, with Kansan and Kenyan roots, foreign or American? Black or white?

In a letter to a previous girlfriend, the president wrote, "Caught without a class, a structure, or tradition to support me, in a sense the choice to take a different path is made for me The only way to assuage my feelings of isolation are to absorb all the traditions [and] classes; make them mine, me theirs.'"

While this is the first time the public is learning her name, Cook is referenced in the president's memoir "Dreams From My Father," where he describes her as the white woman he met in New York.

Maraniss writes in Vanity Fair, "Early in Barack's relationship with Genevieve, he had told her about 'his adolescent image of the perfect ideal woman' and how he had searched for her 'at the expense of hooking up with available girls.' Who was this ideal woman? Genevieve conjured her in her mind, and it was someone other than herself. She wrote, 'I can't help thinking that what he would really want, be powerfully drawn to, was a woman, very strong, very upright, a fighter, a laugher, well-experienced - a black woman I keep seeing her as.'"

In his book, the president describes taking his New York girlfriend to a play by a black playwright and later fighting with her over race. "She couldn't be black, she said," Obama wrote. The president later acknowledged in talking with Maraniss that the incident did not involve Cook.

"That was an example of compression I was very sensitive in my book not to write about my girlfriends, partly out of respect for them," the president told him.

Obama's relationship with Cook is described by Maraniss as the "deepest romantic relationship of his young life" and yet "when she told him that she loved him, his response was not 'I love you, too' but 'thank you '- as though he appreciated that someone loved him."

Cook and Obama ultimately broke up in 1985. "I guess I hoped time would change things and he'd let go and 'fall in love' with me. Now, at this point, I'm left wondering if Barack's reserve, etc. is not just the time in his life, but, after all, emotional scarring that will make it difficult for him to get involved even after he's sorted his life through with age and experience," Cook wrote at the time.