She studied at King"s College, Cambridge and the College of Law, working as a solicitor for 13 years.
Her travels have provided some of the inspiration for her writing. Her interests include collecting Asian ball-jointed dolls, Richard III, Sasha dolls, myth, and East European music Her first novel, Children of the Shaman, was published by Orbit in 2001, and was short-listed for the Locus magazine best first novel in 2002.
A sequel, The Glass Mountain, appeared in October 2002.
A short story, The Anniversary, was published in an anthology printed by NewCon Press in 2010 to celebrate the fifth anniversary of The Write Fantastic. Rydill"s third novel, Malarat, was published in eBook format on 1 May 2013.
Both Children of the Shaman and The Glass Mountain are available as eBooks, having been reissued in 2014. The cover art for the series is by Truenotdreams Design.
In 2006, Rydill married Stephen Saunders, a writer and designer.
Her sister Sarah Ash, author of the Tears of Artamon trilogy, is also a fantasy novelist.