Mary Pope Osborne

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. 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...

The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!
Three …two…one…BLAST OFF! The Magic Tree House whisks Jack and Annie off to the moon—and the future. Their mission? To find the last "M" thing that will free Morgan from the spell. Can they do it before the air in their oxygen tank runs out? Will the mysterious moon man help them? And why is...

The magic tree house carries Jack and Annie to New York City in 1938 on a mission to rescue the last unicorn. The city is in the grip of a terrible snowstorm. To stop the blizzard, Jack and Annie must save the unicorn made famous in the Cloister's medieval tapestries. But will that be enough to help a city that faces so many troubles?

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.

The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!
Jack and Annie are headed to a land of fierce samurai and great beauty, the capital city of Edo (now the city of Tokyo), in ancient Japan in the 1600s. They bring only a research book to guide them and a magic wand with three special rules.
Formerly numbered as Magic Tree House #37, the title of this book is now

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The magic tree house takes Jack and Annie to Antarctica to search for the fourth secret of happiness for Merlin.

Jack and Annie are joined by Teddy and Kathleen as they travel to the snowy Land-Behind-the-Clouds, where they search for the eye of the Ice Wizard and attempt to help Merlin and Morgan.

The magic tree house takes Jack and his sister Annie to the Great Plains where they learn about the life of the Lakota Indians.

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.

The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!
Beware of avalanches! When the magic tree house whisks Jack and Annie back in time to the highest pass in the Swiss Alps, they discover an ancient monastery filled with monks and Saint Bernard dogs. Annie can’t resist offering to train a wild young dog named Barry, but he is quite the handful! Before the night is...