From critically acclaimed and prolific author Jane Yolen comes a delightfully funny Level 2 Ready-to-Read story that puts a twist on a classic a knock-knock joke! Knock, knock... Who's there? It's Interrupting Cow. Interrupting Cow wh--! Well, you know how the joke goes...or do you? Read this side-splitting book to discover the true, surprisingly heartwarming story of the one and only Interrupting Cow!