I haven't read it yet, but I have heard about it. One major thing I should warn you to do is to take Jacobs's claims with a grain of salt. A lot of his information comes from hypnosis sessions on abductees, and hypnosis has been proven to be an EXTREMELY UNRELIABLE tool for recovering memory. A lot of the information in those sessions could have been fabricated by leading questions, hypnotic suggestion and confabulation.
David Jacobs has a degree in American history, but he has NO psychiatric credentials and no medical or psychological training whatsoever.
Regressive hypnosis in the hands of someone like Jacobs can EASILY lead to the creation of false memories. Look up False Memory Syndrome online.
I'm not saying alien abductions don't happen. I believe alien abductions can happen. I just don't believe that aliens like the Greys are planning to take over, and I not only question the conclusions that Jacobs has come to, but also and especially his unethical methods to get to those conclusions.
Read up about the Emma Woods case to find out why I'm disillusioned with Jacobs as a reputable researcher.