When Jack and Annie came back from their adventure in Magic Tree House #29: A Big Day for Baseball, they had lots of questions. When was baseball invented? What are the rules? Who was Jackie Robinson? Who are some other baseball greats? Find out the answers to these questions and more as Jack and Annie track the facts about America’s national pastime. Filled with up-to-date information, photographs, illustrations, and fun tidbits from Jack and Annie, the Magic Tree House Fact Trackers are the perfect way for kids to find out more about the topics they discover in their favorite Magic Tree House adventures. And teachers can use the Fact Trackers alongside their Magic Tree House fiction companions to meet Common Core text pairing needs.