Hi guys!
Alien invasion should be considered a "Core Book" in that, we had to start someplace.
So, yes, you'll see Majestic 12 stuff. Michael Tresca did his homework on Maj-12. I think it's a very good resources for people who want to use it as a primer for an "X-files" type of campaign. We have stats for various types of antagonists you'll see; Pounce Agents, Aquarious scientists, Delta Security teams, etc.
These use modern stats, they are by no means "retro."
I think Area-51 was referenced maybe once in the entire document. Area-51 is fairly cliche, so I think Mchael wanted to stray from using the base. We included a run-down of many nations which are rumored to have these types of bases. There are fully illustrated maps of each level of a typical secret military base with explainations of what you might find on each level. This could fit within the Area-51 concept, if you are interested in that sort of thing.
You'll see a brief history on extreterrestrials... very brief.
You'll find rules for using cattle mutilations and rules that determine what can happen to you if you investigate a crop Circle.
Alien abductions are also thoroughly detailed. We included rules on how to use Alien implants and what sort of effects they will have on characters.
There are 4 new templates, new backgrounds ( including the Abductee), new weapons, new spaceships, and new alien races. Fringe elements and alien cults, such as Raelians, are also covered in this book.
As I said before, this should be considered a "core book" in that we plan on moving forward with supplements and adventures. We plan on adding new advanced classes, new organizations with their own agendas, and eventually even a mammoth supplement that expores a full-blown "war of the worlds" type of scenario.
I hope this helped.