世界各地成千上万人所目击的UFO是真是假？"太空来客""水星生命 "是否确实......本书涵盖了外星人研究领域中最有趣味、最被关注和最具价值的内容。以通俗易懂、深入浅出的语言将大量目前科学还无法解释的事物和现象讲述给青少年读者。Is the UFO witnessed by tens of thousands of people around the world real or fake? Do "Space visitors" and "Mercury life" exist? ...The book covers the most interesting, most watched and most valuable contents areas in the alien research. The book explains things and phenomena which are hard for current science to explain to young readers in plain and simple language.