Once upon a time (but not too long ago), girls only wore dresses. And only boys wore pants. Until one day, a young girl named Mary had a bold idea: She would wear whatever she wanted. And she wanted to wear pants! Inspired by the true story of Mary Edwards Walker, a trailblazing doctor who was arrested many times for wearing pants, this fresh, charming picture book encourages readers to think for themselves while gently challenging gender and societal norms.