The Real Men in Black
You have likely seen the movie Men in Black with Will Smith, but these Men in Black are far less friendly a whole lot less lovable. In The Real Men in Black, Nick Redfern, a veteran of many paranormal topics, explores sightings, theories and possible explanations for the phenomenon known as the MIB.
For decades or even longer, when something paranormal happens, particularly a UFO sighting, the MIBs seems to know it is going on and are there to ask questions of witnesses and silence them if they need to.
As usual, Nick does a good job of covering historical accounts of Men in Black as well as more modern sightings and encounters. As a foundational book on MIBs, this book get a passing grade from me.