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.

Blizzard of the blue moon: Jack and annie go back in time to New York City, during one of the darkest periods in the city's history--the Great Depression. Even worse, 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 facews so many troubles?...

"The magic tree house whisks Jack and Annie away to South America, where they must climb Machu Picchu to save a baby llama" -- Provided by publisher.

Jack and Annie aren't great baseball players...yet! Then Morgan the librarian gives them magical baseball caps that will make them experts. They just need to wear the caps to a special ballgame in Brooklyn, New York. The magic tree house whisks them back to 1947! When they arrive, Jack and Annie find out that they will be batboys in the game, not ballplayers. What exactly does Morgan want them to learn? And what's so special about this game? They...

"Jack and Annie are whisked back in time by the magic tree house to meet Benjamin Franklin in Old Philadelphia"--