Knock Knock Who's There - Puppet Book Author:Christopher Cerf, Gene Barretta Fans of the Between the Lions series on PBS will love this puppet book. Adorable Lionel and Leona puppets are incorporated into every page so your child will be able to watch the cubs move and tell knock-knock jokes. Between the Lions was recently named Best Children's Program by the Television Critics Association. It has also been endorsed by t... more »he National Education Association, the nation's largest teachers organization. READING LEVEL: Ages 4-8« less