I loved this book so much, and as I do when I love something, I dug around for more info. I found that there have been several adorable adaptations of the book. My favorite is the Dr. Who version which you can find here: http://doctorwho.tumblr.com/post/12891889415/i-want-my-hat-back-the-doctor-edition
Then what I found is some self-plagiarism by Mr. Klassen in another wonderful book that he illustrated called Extra Yarn, by Mac Barnett.
These are clever, fun books with fantastic illustrations. Find these and more at your local library!