Mary Pope Osborne

A good night for ghosts: Jack and Annie must travel back in time to New Orleans in 1915 to help a teenaged Louis Armstrong fulfill his destiny and become the "King of Jazz." -- Leprechaun in late winter: 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.

K-3. Hurry up, Houdini!: "Join Jack and Annie as they as they meet one of the world's most famous illusionists - Harry Houdini!"-- High time for heroes: "Jack and Annie are magically transported to mid-1800's Thebes where they are saved from a dangerous accident by Florence Nightingale!"--

Merlin the magician will not eat or sleep or speak to anyone. The enchantress Morgan asks young Jack and Annie of Frog Creek, Pennsylvania for help. Jack and Annie know they have to search for one of the four secrets of happiness to help Merlin the magician find joy in his life again. And so they head off in the magic tree house for Florence, Italy, in the early 1500s, then to a misty island in the middle of nowhere, then to the continent of Antarctica....

A perfect time for pandas: Magically transported to southwest China to find the final object needed to break the spell on the wizard Merlin's beloved penguin, Jack and Annie take a side trip to the world's largest giant panda reserve. Stallion by starlight: "Travel to Ancient Greece with Jack and Annie as they meet Alexander the Great and help tame his wild stallion"--

The one-eyed giant: When Odysseus leaves his home to fight in the Trojan War, he never imagines that he'll be away from his family for so many years. Now he is leading his men across the seas. Among the dangers that await them is Polyphemus, the one-eyed giant. The land of the dead: The curse of Polyphemus plagues them at every turn while Odysseus and his men face giant cannibals and outwit a beautiful witch, who reveals Odysseus's next challenge--...

Carnival at candlelight: 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! Season of the sandstorms: Armed only with a research book and a book of magic rhymes, Jack and Annie to back 1,200 years to the Golden Age of...

Stallion by starlight: travel to Ancient Greece with Jack and Annie as they meet Alexander the Great and help tame his wild stallion. Hurry up, Houdini!: join Jack and Annie as they as they meet one of the world's most famous illusionists - Harry Houdini! High time for heroes: Jack and Annie are magically transported to mid-1800's Thebes where they are saved from a dangerous accident by Florence Nightingale! Soccer on Sunday: Jack and Annie search...

Describes the changing nature of weather and how meteorologists predict and study such storms as tornadoes, hurricanes, and blizzards.

Jack and his younger sister, Annie, go on a series of extraordinary adventures as they use their magical tree house to travel through time.

Jack and Annie go on a series of missions in order to help the wizard Merlin, traveling to such places as Japan, Antarctica, New Orleans, and Ireland.