Kallie George is the author of the Crimson Twill books as well as several picture books for young children, including The Doll Hospital, illustrated by Sara Gillingham, and Secrets I Know, illustrated by Paola Zakimi. She is also the author of the Heartwood Hotel chapter book series, illustrated by Stephanie Graegin, among many other books for children. Kallie George lives with her family in Vancouver, British Columbia.

Birgitta Sif is the author-illustrator of the picture books Oliver and Frances Dean Who Loved to Dance and Dance. She is also the illustrator of Snowboy and the Last Tree Standing by Hiawyn Oram, The Tall Man and the Small Mouse by Mara Bergman, and Hugo by Atinuke, as well as the Crimson Twill adventures. Originally from Iceland, Birgitta Sif lives with her family in Sweden.