Mary Pope Osborne

Eight-year-old Jack and his younger sister Annie find a magic treehouse, which whisks them back to an ancient time zone where they see live dinosaurs.

Their magic tree house takes Jack and Annie deep into the sea, where they meet up with dolphins, sharks, and octopi as they search for the answer to an ancient riddle.

Their magic tree house takes Jack and Annie back to the Wild West, where they experience excitement and danger and try to solve a riddle.

Their magic tree house takes Jack and Annie back to a monastery in medieval Ireland, where they try to retrieve a lost book while being menaced by Viking raiders.

Eight-year-old Jack and his younger sister Annie use the magic treehouse to travel back to the Middle Ages, where they explore a castle and are helped by a mysterious knight.

The magic treehouse takes Jack and Annie back two thousand years to ancient China where they must find the original copy of an old legend before the Imperial Library is burned down by the evil Dragon King.

Their magic tree house takes Jack and Annie to the Arctic, where a polar bear leads them onto very thin ice.

"Join Jack and Annie as they as they meet one of the world's most famous illusionists - Harry Houdini!"--

The magic tree house takes Jack and Annie to Africa where they meet up with wonderful wild animals, a very hungry warrior, and where they even solve a riddle.

While on a mission to prove to Merlin that they can use magic wisely, Jack and Annie travel to seventeenth-century Venice, Italy, to save the city from disaster. Merlin has asked Jack and Annie to help on another Merlin Mission. This time they head back into history to Venice, Italy, in the 1700s. With the help of some new friends, a research book, and a mysterious rhyme from Merlin, the heroes will save the beautiful city from a flood! Yet another...