Unidentified phenomena in space in the Earth's atmosphere and in waters are too important to
leave their exploration to the military and scientific laypersons. Their proper scientific
study is important for a variety of reasons in particular scientists and the public at large
need to know the basic facts to be informed about the way evidence is recorded and to
understand the difference been reliable evidence and fiction as well as between plausible
explanations and fantasy. With this objective the book surveys the history of UFO observations
the variety of recorded phenomena and recounts the efforts of investigative commissions and
their published findings. Although wild rumors are demystified in the process this is not an
exercise in rumor-bashing. An open and at the same time critical mindset is the key. Many
narratives and hypothesis appear implausible relative to our present state of knowledge but
this alone should not lead to their outright exclusion. Thus the author also pays attention to
UFO sightings that have so far eluded explanation in terms of known physics or meteorology.
Here the reader will encounter some of the more speculative but scientifically tenable
proposals for example relating to sudden zigzag motion without apparent inertia or
recognizable propulsion yet always with a clear guide to their plausibility. Last but not
least the book outlines plans and suggestions for future research capable of revealing the
existence and intentions of extraterrestrial intelligences outer-space engineers or
technologies so far known only from science fiction.
