Michael Dahl is the prolific author of the bestselling Goodnight, Baseball picture book and more than 200 other books for children and young adults. He has won the Association of Educational Publishers Distinguished Achievement Award three times for his nonfiction, a Teachers' Choice Award from Learning Magazine, and a Seal of Excellence from the Creative Child Awards. Dahl currently lives in Minnesota.

Two of the world's greatest superheroes, Batman and Batgirl, demoonstrate the importance of teamwork.