Once we had entered the space age, we could have reasonably expected that the days of 'flying saucers' and 'little green men' would ave come to an end. Instead, the evidence for UFOs continues to grow. There are literally tens of thousands of sightings on record, most of them made by reliable witnesses and many of them still unexplained; close encounters of the fourth kind - abduction - are becoming more frequent, well documented and harder to ignore; evidence in the files of serious scientific and investigative bodies (including the United States Air Force) leaves little doubt that an 'intelligence' is operating - but what kind and from where? Do extra-terrestrials regularly visit the earth? Are we being watched, studied, contacted and even kidnapped by intergalactic explorers? This book presents forty years of evidence and facts for the sceptic and believer alike - case histories, expert assessments and possible explanations. Illustrated with black and white photographs