The#1 bestselling chapter book series of all time celebrates 25 years! 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