Extreme Mileage 101 | www.eagle-research.com
200 MPG in a 2000 pound vehicle should be easy according to these guys. I didn't buy the book, and can't recommend anyone else buy it.
In the top link if you click on the picture of the book cover it becomes a pop-up in the middle of your screen. Click the Next button to see a preview of 5 of the pages and you can read some of the claims being made.
Also, look here:
Eagle-Research:
Here's another one of their claims:
For that one, assuming that even works, couldn't one just buy higher octane gas? Also, IIRC higher octane gas does NOT help most cars. This guy seems like a quack.