What was that strange light in the sky? No one knows! It's an unidentified flying object, or UFO. Many UFOs turn out to be aeroplanes or clouds. But some people say aliens visit Earth in UFOs. Could that be true? Researchers use cameras, magnetic field sensors, telescopes, radar and other gear to find out. In this book, readers will get an inside look at the high-tech tools used to study UFOs. What is more, the carefully levelled text will ensure that even struggling and reluctant readers will succeed in reading and enjoying the book.