Knock-Knock . What’s here? A knock-knock for every day of the year! Knock-knocks are perennial favorites with kids, and they’ll find more than enough yuks on these pages to share with their family, friends, and anyone else for a long time to come. They can try this one with their teachers: “Knock Knock . Who’s there? Dewey . Dewey who? Dewey have to do our homework tonight? The librarian will like this one: “Knock Knock . Who’s there? Cohen. Cohen who? Cohen home after I return these books .” Adorable and energetic art adds to the fun.