The Day Santa Stopped Believing in Harold by Maureen Fergus
Santa has a problem. This kid? Harold? Santa doesn't think he's real. He WANTS to believe in Harold--after all, Harold is one of the most magical parts of Christmas. Getting Harold's letters, eating the cookies he leaves out, feeding his carrots to the reindeer...what would Christmas be without that? But Santa's just not sure. Some of his friends are telling him they think Harold's not real. And the Harold that sat on his knee last Christmas looked AWFULLY different. Santa comes up with a plan to find out once and for all if Harold really exists...with hilarious consequences.