Gwyneth Rees is half Welsh and half English and grew up in Scotland. She went to Glasgow University and qualified as a doctor in 1990. She is a child and adolescent psychiatrist but has now stopped practising so that she can write full-time. She is the author of many bestselling books, including the Fairies series, the Cosmo series and the Marietta's Magic Dress Shop series, as well as several books for older readers. Gwyneth's new books, My Super Sister and My Super Sister and the Birthday Party mark the start of an exciting new series about two sisters, Emma and Saffie, who have superpowers! She lives near London with her husband, Robert, their daughters, Eliza and Lottie. Lydia Monks is one of the most original and bestselling picture book artists working today. Lydia illustrates several bestselling series including the What the Ladybird Heard adventures and Princess Mirror-Belle, written by Julia Donaldson. Her distinctive use of colour and collage has won her critical acclaim and several awards, including the Royal Mail Scottish Children's Book Award, the Stockport Children's Book Award and multiple nominations for the Kate Greenaway Medal. Mouse's Big Day, written and illustrated by Lydia, is the first book in her Twit Twoo School series. Lydia lives in Sheffield.