Guaranteed to leave you in stitches! If you can't resist shouting out "Who's there?" on cue, The Everything Kids' Knock Knock Book is for you! Features hilarious sections such as: Once Upon a Knock Knock When Fun Comes a Knockin' Tied Up in Knock Knocks Knock Knock Your Socks Off Who's That Knockin'? Packed full of puzzles, games, and activities, The Everything Kids' Knock Knock Book proves that laughter really is the best medicine!