Mary Pope Osborne

Having used their magic tree house to travel to India, where they must get a gift to help free the dog Teddy from a spell, Jack and Annie have adventures involving a tiger and other endangered jungle animals.

The magic tree house whisks Jack and Annie to Washington D.C. in the 1860s where they meet Abraham Lincoln and collect a feather that will help break a magic spell.

As a thank-you from Merlin and Morgan, Jack and Annie are sent on what should be a vacation at a luxurious resort in Cozumel, Mexico, but is, by mistake, an adventure with ancient Mayans, instead.

When the magic tree house whisks Jack and Annie off to Greenland, they're not sure what time they've landed in, but they immediately know what their mission is: save a narwhal! Then they meet a young hunter named Leif Erikson and they ask for his help. But Leif has other ideas...

"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.

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 transports Jack and Annie on a mission to the Ice Age where they encounter Cro-Magnons, cave bears, sabertooth tigers, and woolly mammoths.

Jack and his younger sister take a trip in their tree house back to ancient Egypt, where they help a queen's mummy continue her voyage to the Next Life.

Their magic tree house takes Jack and Annie back to a monastery in medieval Ireland, where they try to retrieve a lost book while being menaced by Viking raiders.

It is a dark and snowy night when the magic tree house whisks Jack and Annie back to the Revolutionary War. General George Washington is about to lead his army in a sneak attack against their enemy. But now the terrible weather is making the great general question his plans. Can Jack and Annie keep history on track? The fate of the country rests in their hands!