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?" --

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.

"When Jack and Annie receive an invitation to spend Christmas Eve in Camelot--a magical place that exists only in myth and fantasy--they know they are in for their biggest adventure yet. What they don't know is that the invitation will send them on a quest to save Camelot. Can they succeed even though Camelot's greatest knights have failed?"--Amazon.com.

Jack and Annie travel back to nineteenth-century Ireland to inspire a young Augusta Gregory to share her love of Irish legends and folktales with the world.

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 tree house whisks Jack and Annie to India during the Mogul Empire in the 1600s to search for an emerald needed to break a magic spell.

Eight-year-old Jack, his seven-year-old sister, Annie, and Peanut the mouse ride in a tree house to the Amazon rain forests, where they encounter giant ants, flesh-eating piranhas, hungry crocodiles, and wild jaguars.

"When the magic tree house whisks Jack and Annie back in time, they land in the tallest tree in Yosemite, California where they join nature conservationist, John Muir, and US President Teddy Roosevelt on a historic trip through the woods"--

Jack and Annie search for the fourth secret of greatness for Merlin the Magician in Mexico City at the 1970 World Cup Games where they hope to learn something new from soccer player great Pele.

Jack and Annie are whisked back in time to Old Philadelphia by the magic tree house to meet the Founding Father, journalist, and famous inventor Benjamin Franklin.