This book is fascinating for a couple of reasons
1. It gives a historical account of how people reacted to some of the big "UFO events" in the 40's and 50's. That alone made for some really good reading.
2. Ruppelt gives the reader a good 'feel' for how the military felt about UFO's. It was quite interesting to read how the military went from "convinced" to the UFO being extra-terrestrial to being convinced it was natural phenomena or people's imagination.
I am neither a believer nor skeptic of UFOs being extra-terrestrial... I just don't know. What I will say is that the book doesn't attempt to sway you one way or the other.