Mary Pope Osborne

"Where did the tree house come from? Before Jack and Annie can find out, the mysterious tree house whisks them to the prehistoric past. Now they have to figure out how to get home. Can they do it before dark ... or will they become a dinosaur's dinner?" --

Jack and his younger sister take a trip in their tree house back to ancient Egypt, where they help a queen's mummy continue her voyage to the Next Life.

It's a treasure trove of trouble! Jack and Annie are in for a high-seas adventure when the magic tree house whisks them back to the days of deserted islands, secret maps--and ruthless pirates! Will they discover a buried treasure? Or will they be forced to walk the plank? The magic treehouse whisks Jack and Annie back to the days of deserted islands, secret maps, hidden gold, and nasty pirates.

The magic treehouse takes Jack and Annie to a moon base in the future where they continue to search for the fourth thing they need to free their friend Morgan from the magician's spell.

Their magic treehouse 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. Morgan le Fay will make Jack and Annie masters of the tree house if only they can solve four riddles -- which will take four books, of course! Dolphins at Daybreak begins the third set of four books in this magical (and increasingly popular) series! Jack and Annie are off in the Magic...

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.

Using the magic treehouse, Jack and Annie travel 500 years back in time to Florence, Italy, and spend a day helping Leonardo da Vinci in the hope of learning another secret of happiness.

Traveling in the magic treehouse, Jack and Annie visit the Paris World's Fair of 1889 in an effort to protect four scientific pioneers from an evil sorcerer.

The magic tree house whisks Jack and Annie away to Australia where they must save some animals from a wildfire.

Jack and Annie are all shaken up! The magic tree house whisks them back to California in 1906. As soon as they arrive, the famous San Francisco earthquake hits the city. Can Jack and Annie find the final writing they need to help Morgan save Camelot? Or will San Francisco be destroyed first?