"The Hunt for Zero Point" by Nick Cook.
I downloaded this pdf book from somewhere and just finished reading it.
I hardly read much these days, in the way of books, but this caught
my attention, and it is very interesting.
For those who know - Nick Cook writes for the Janes Defence Weekly
normally and this book has been written in his spare time over many
years.
It actually covers a great deal about the Nazi Super secret weapons
of WWII and other such technologies.
Zero Point is in reference to Zero Point energy or free energy,
of being able to produce unlimited energy from energy that is all
around us - a holy grail, as it were.
There is a lot of history detailed here, as regards the various
American supersonic jetplane developments over the years of the
emergence of the stealth technology - so any aeronautical buff wanting 
to know more about the US aerospace industry would find this immediately
appealing.
For those who think that Zero Point energy is just hoopla without
substance, just do a google search for Tom Bearden and MEG - to see
that just possibly it is just emerging now, into the general science
and home area?
It is interesting to note the point made in the book, about great
inventors, that they see something in nature that gets their thought
processes going...
I was watching this documentary about active volcanoes over the world,
and how various keen people film the active volcanoes, and at the
end of this programme, they show a close up of a smoke ring that
exits a prominent volcano, noting this 30? or 60? year event.
What was interesting about the close up detailed shot, is how it
shows clearly the whirling vortices of this toroid (doughnut)
smoke ring that was projected high into the air, still retaining it's
shape --- is that I have a diagram of an electromagnetic field
being generated by a rotating toroid at one of my homepages
http://plain2.tripod.com/various.htm
as being the motor for a UFO type craft? And mention is made of
such possibilities in the above book, that a rotating toroid is a key.

Harvey