Kiran Desai has won the UK's leading literary award, the Man Booker Prize, for her novel The Inheritance of Loss.
Desai is the daughter of author Anita Desai
She picked up the £50,000 prize after being chosen by a panel of judges from a shortlist of six.
Desai beat favourite Sarah Waters - shortlisted for The Night Watch - and fellow nominees Kate Greenville, Hisham Matar, M J Hyland and Edward St Aubyn.
Desai, 35, is the youngest female winner of the prize. The Inheritance of Loss is her second novel.
She dedicated the novel to her mother and fellow novelist Anita Desai who has herself been nominated for the Booker prize three times, but has never won.
Desai told the BBC her win felt "like a family endeavour".
"I wrote this book so much in her company it feels almost like her book," she said.
The judges hailed The Inheritance of Loss as "a magnificent novel of humane breadth and wisdom, comic tenderness and powerful political acuteness".
Hermione Lee, chairwoman of the judges, said: "I think her mother would be proud.
"It is clear to those of us who have read Anita Desai that Kiran Desai has learned from her mother's work.
"Both write not just about India but about Indian communities in the world.
"The remarkable thing about Kiran Desai is that she is aware of her Anglo-Indian inheritance - of Naipaul and Narayan and Rushdie - but she does something pioneering.
"She seems to jump on from those traditions and create something which is absolutely of its own.
"The book is movingly strong in its humanity and I think that in the end is why it won."
Desai added: "It was seven, almost eight years of work, writing half stories, quarter stories, stories in eighths, of broken people, difficult lives and I picked the novel out of it.
"It was quite a difficult, emotional experience for me. I think I was devastated and sad by the end of the book."
Sarah Waters had been favourite to win the award.
But on Monday bookmakers reported a surge in people backing Desai.
Sarah Waters - The Night Watch
Kiran Desai - The Inheritance of Loss
Edward St Aubyn - Mother's Milk
Kate Greenville - The Secret River
M J Hyland - Carry Me Down
Hisham Matar - In the Country of Men
The Inheritance of Loss tells the story of a Cambridge-educated Indian judge who lives a reclusive retirement in the foothills of the Himalayas.
But the arrival of his orphaned teenage granddaughter, and his cook's son's attempts to keep one step ahead of the US immigration department, threatens to shatter his peace.
Desai herself lived in India until the age of 15, when she moved to England to continue her education, and currently lives in the US
She said she returned to India to write parts of the novel.
"I went back to write the Indian bits in India, so it wasn't entirely from a distance."
Desai's mother was not at London's Guildhall to hear her daughter scoop the prestigious prize.
"I think she was so terrified on my behalf that she retreated as far as she could," said Desai.
"She gave me lots of advice and now she is without a phone and without a television in a village in India."