Derek
If you want a facinating and VERY thought-provoking read, then try this:
The DAY AFTER ROSWELL
by Philip Corso, William J. Birnes "
I read it several years ago and coulldn't put it down. It's well-written by someone with a high US military clearance, who claims he was there and was a lead figure in the investigation.
In short, he claims it was all true, and goes into great detail listing and describing all the inventions that we have seen since and as a result of reverse engineering of what they found.
A truly facinating read. If you do a GOOGLE search you will find it.
Cheers....LC