Tom Swift and His Giant Cannon is a book in the Tom Swift series by Victor Appleton. In this book, Tom and his friends must build and use a giant cannon to rescue a group of explorers who are lost in the Amazon jungle. They face many challenges along the way, including dangerous animals, treacherous terrain, and rival inventors who want to steal their invention. The team must use their ingenuity and determination to save the explorers and make the longest shot on record.