Book to reveal intimate details of young Barack Obama's love life

US President Barack Obama had a fling with an Australian woman in New York during 1980s and a new biography threatens to bare this torrid affair.

Secret diaries of Genevieve Cook, daughter of an Australian diplomat, who was one of young Obama's girlfriends are being carried in the forthcoming book Barack Obama: The Story that captures intimate details of his love life.

The Vanity Fair magazine carries the extracts of the diaries from the book in its latest issue and the biography has already become the talk of the town Down Under.

Obama confessed to the author of the book, David Maraniss, that "woman in New York" was a "compression" of several girlfriends he had in New York and Chicago.

Maraniss had access to Cook's diaries and they shed light on the character and personality of the young Obama to show the warmth and trust of the future president in love.

Her memories range from the trivial to the controversial.

Cook reveals that on Sundays Obama loved to lounge around and do the newspaper crossword.

She also recounted how he was deeply confused about his racial identity and "felt like an imposter because he was so white."

She claims that in the end, Obama decided that he needed to 'go black' because it was best for him.

Cook has long been hailed as the 'mystery woman' from Obama's past days in New York that he wrote about in his own memoir.

Excerpts from the book reveal that Obama and Cook met at a Christmas party in New York's East Village in December 1983 when she was 25, three years older than him.