The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!

Gentle giants or giant monsters? That's the question Jack and Annie have about gorillas when the Magic Tree House sweeps them to the mountains of Africa. There they meet a group of amazing and sometimes frightening mountain gorillas. Annie knows how to play with the creatures right away. But Jack is left out. Will the gorillas be able to teach him some special magic?