Christelle Dabos was born on the Côte d'Azur in 1980 and grew up in a home filled with classical music and historical games. She now lives in Belgium. The Mirror Visitor, her debut series, won the Gallimard Jeunesse-RTL-Télérama First Novel Competition, and every book in the series has proved to be a runaway bestseller. A Winter's Promise was shortlisted for Waterstones' Children's Book Prize in 2019.

Since graduating in French from Oxford University, Hildegarde Serle has worked in London as a subeditor, mainly on The Independent. In 2011, she did the CIOL Diploma in Translation. She still lives in London, but her heart lives on the Quai aux Fleurs in Paris.