The 1 bestselling chapter book series of all time celebrates 25 years with new covers and a new easy-to-use numbering system Jack and Annie are on a mission to save Merlin from his sorrows The brother-and-sister team travel back in the magic tree house to the period known as the Renaissance. This time Jack and Annie will need more than a research book and a magic wand. They'll need help from one of the greatest minds of all time. What will they learn from Leonardo da Vinci? Formerly numbered as Magic Tree House 38 the title of this book is now Magic Tree House Merlin Mission 10: Monday with a Mad Genius. 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. Language: English