The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!
Merlin's beloved penguin, Penny, has been put under a spell! To save her, Jack and Annie must find a rare and precious emerald. When the magic tree house whisks them back to India over four hundred years ago to search for the jewel, they discover an amazing and exotic world filled with great danger.
Formerly numbered as Magic Tree House #45, the title of this book is now Magic Tree House Merlin Mission #17: A Crazy Day with Cobras.
Did you know that there's a Magic Tree House book for every kid?
Magic Tree House: Adventures with Jack and Annie, perfect for readers who are just beginning chapter books
Merlin Missions: More challenging adventures for the experienced reader
Super Edition: A longer and more dangerous adventure
Fact Trackers: Nonfiction companions to your favorite Magic Tree House adventures
Have more fun with Jack and Annie at MagicTreeHouse.com!

MARY POPE OSBORNE is the author of the New York Times number one bestselling Magic Tree House series. She and her husband, writer Will Osborne (author of Magic Tree House: The Musical), live in northwestern Connecticut with their three dogs. Ms. Osborne is also the coauthor of the companion Magic Tree House Fact Trackers series with Will, and with her sister, Natalie Pope Boyce.
 
SAL MURDOCCA has illustrated more than 200 children's trade and text books. He is also a librettist for children's opera, a video artist, an avid runner, hiker, and bicyclist, and a teacher of children's illustration at the Parsons School of Design. Sal lives and works in New York with his wife, Nancy.