The Camp Knock Knock MysteryPaperback - 1997
Willie and Crow are back at camp. Last year, Willie won the joke contest and was the knock-knock king. Now Crow wants to get him back. But Willie has a secret weapon--or does he? This time Crow takes charge as Willie must solve the clues hidden in knock-knock jokes to get back his secret weapon--a knock-knock joke book.
Publisher: New York : Bantam Doubleday Dell Pub., 1997.
Characteristics: 46 pages :,color illustrations ;,20 cm.