Rosen is a bestselling author, who writes fiction for children and adults.She was born in Cornwall and grew up on Restronguet Creek. She studied Experimental Psychology at St Catherine's College, Oxford, before moving back to the West Country. She now lives on the south coast of Devon with two imaginary cats, fantasising about getting a real one.In 2011 Rosen was an aspiring author. Writing was a hobby. The following January sales of her books on Kindle took off, and by October she has sold 27,000 copies and her total download count exceeds 220,000. She now has three books in print: Pompomberry House, Seesaw and The Troll Trap, as well as many digital titles.Rosen writes in a variety of genres with a strong leaning towards comedy. She has also dabbled with psychological fiction and mystery writing. She loves wild swimming, mountain biking, interesting boots, quiffs, 'sampling' chocolate and cooking tasty treats. She dislikes house spiders, doing laundry and people putting costumes on their cats.