The agency's first task will be to create a campaign to promote Nora Roberts latest novel, 'High Noon', in the UK. The work is expected to break in early summer.
Roberts is one of America's best-selling authors. Her novels have spent 660 weeks on the New York Times Bestseller List, including 100 weeks in the number one spot.
She has been published in 35 countries and more than 280m copies of her novels are in print.
Roger Cazalet, the group marketing director at Little, Brown Book Group said: "Quiet Storm's creativity shone through and we're delighted to be working with them."
Jon Howard, strategy director at Quiet Storm, said: "Little, Brown is a dynamic business, filled with people who are passionate about what they do, and where every project is effectively a launch. It's a very exciting opportunity for us."
Little, Brown Book Group has won the KPMG publisher of the year award twice and has a string of top sellers in each season.
Last month, Associated Newspapers appointed Quiet Storm to handle its London Lite account.