J.K. Rowling’s 2020 children’s book about a boy called Jack was The Ickabog.
The Ickabog is a standalone political fairy tale set in the fictional kingdom of Cornucopia. Its central story follows children who confront a frightening legend and the abuses of power that grow around it. Jack is one of the young characters involved in the story, alongside Bert and Daisy.
Rowling originally wrote the book for her own children and later published it in instalments online during 2020. She invited children to submit illustration ideas for a competition, and selected entries were used in the printed edition. The book was published in support of charitable causes connected with the COVID-19 pandemic.
The Ickabog is not part of the Harry Potter series and does not share its wizarding setting. It is also separate from Rowling’s later children’s novel The Christmas Pig, which was published in 2021 and follows a boy named Jack and a lost toy pig.