Synopsis: The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system! Getting the facts behind the fiction has never looked better. Track the facts with Jack and Annie!!   When Jack and Annie got back from their adventure in Magic Tree House #16: Polar Bears Past Bedtime, they had lots of questions. Why is the Arctic so cold? What did the first people of the Artic eat? How do polar bears…

Synopsis: Dandan has always dreamed of visiting her father, who is away studying icebergs at the South Pole. Now, thanks to a new post office policy, she can mail herself there--but not without a few adventures along the way.