First published in 1995, and in some ways, the scientific approach is dated ... and what I really mean by this is: the science to assess properly what is or is not possible as far as extraterrestrial XYZ is concerned, has not reached us, yet. But you have to give the author full credit that he takes this subject seriously without going bonkers with it. He sticks to what has been observed. And when he speculates he states clearly that he is speculating. In that sense, definitely worth the while to read it. He manages to add a bit of humor. Never eat an alien, your system will not be able to digest it. Good advise. Conversely, they are not here to eat us, either. OK, that I can believe. He really deserves four stars if not five for all his effort, and the risk he takes to be chucked into the luni-bin drawer.
Scientifically inspired book about UFOs that makes a lot of sense but has a few chapters that I found to be a chore to read. Interesting though and certainly worth reading if you are very much into the UFO phenomena. If you have a general interest in UFOs I doubt this is would be a book for you as it deals with the technicalities of investigations rather than the major investigations themselves.