Billie's best friend is Jack. Even though they are very different, they do everything together and always stand up for each other.
Jack can sometimes be a little shy, but he is the perfect balance to Billie's confident personality. Where she might rush into things without thinking, he is always cautious and thoughtful.
Sally wrote the Jack books as an alternative to all the action hero and funny books most often created for boys, and to help them find ways to explore their feelings. In order to bring up kind and empathetic boys, Sally believes it's vital to offer well-rounded characters for boys to see themselves in or model themselves on.
Like the Billie books, the Jack books are accessible and easy to read, but with enticing storylines to hook kids in.
There are currently 20 books released in the Jack series.