From mysterious luminous orbs to flying saucers, unidentified flying objects have been witnessed in the sky for centuries. Initially assumed to be religious omens or dieties, today we most often associate them with little green men from another planet. Despite their constant presence in our skies, we are seemingly no closer to learning what these curious aerial entities are – or are we? In the immortal words of the X-Files’ Fox Mulder “the truth is out there” – delve deep into the science, history and legacy of this ever-endearing phenomena with The Ultimate Guide To UFOs.