Millions of people have seen them. Thousands claim to have been abducted by them. Astronauts, politicians, fighter pilots and more have witnessed them and history is awash with legends, myths and tales of beings coming down to Earth. They have come and they have interacted with mankind. Great religions have in fact sprung from our contact with them thousands of years ago. Great structures have been built with their aid. Our very genes are a result of their meddling on planet Earth. Prepare to get to grips with the fact that aliens exist.