Debut novelist Ann O'Loughlin is the only Irish author to feature in Amazon UK's list of the top 20 bestselling ebooks of 2015 so far.
Her novel 'The Ballroom Café' was ranked 15th despite only being released in May.
It tells the story of two women dealing with their loss following Ireland's forced adoptions from mother and baby homes to the US.
The book has already sold in excess of 150,000 ebook copies.
The author, a journalist with the Irish Independent for more than 22 years, said she was amazed by the runaway success of her work.
"It's incredible and quite humbling," said Ms O'Loughlin, who is balancing her newfound success as a novelist with a busy career as a High Court reporter for the 'Irish Examiner', as well as being a mother of two teenagers.
"You have no idea when you're writing at five in the morning how people are going to view your writing and that to me has been so heartening," she added.
In a list dominated by women writers, Ms O'Loughlin's novel was ranked alongside Gillian Flynn's 'Gone Girl', EL James's 'Grey' and Paula Hawkins's 'Girl on the Train', which topped the list.