Osborne, Mary Pope

When Merlin is weighed down by sorrows, Jack and Annie travel back to feudal Japan to learn one of the four secrets of happiness.

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

In their magic treehouse, Jack and Annie are again transported to King Arthur's realm, where invisible beings, giant ravens, and mistaken magic spells have a duke's castle in an uproar on Halloween night.

Jack and Annie travel to Vienna, Austria, in 1762, where they meet the young Wolfgang Amadeus Mozart and his sister and help save the budding genius' life.

Jack and Annie continue to try helping Merlin the magician by searching for the secrets of happiness, and their magic tree house takes them to Antarctica, a wasteland where the penguins may know what to do.

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.

Retells the part of Homer's "Odyssey" in which Odysseus is trapped on Calypso's island and his son Telemachus goes in search of him.

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.

A collection of rarely retold tales from the "Elder Edda" and the "Younger Edda," two six-hundred-year-old Norse manuscripts.

Retells twelve tales from Greek mythology, including the stories of King Midas, Echo and Narcissus, the Golden Apples, and Cupid and Psyche.