This is pseudoscientific hooey about classes in the US.
Fussell claims there is a strong class structure in the US,
then goes so far as to describe the classless class and guess
what: it's huge. Given the US has so far less class
orientation than anywhere else on this planet, this book
is a stretch. On the other hand, if you want one man's views on this
are, it's not terribly authored.
Give this a miss unless you have some reason to want to
read on the subject material.
If you want some fun dabbling in this area, try Mayle's
Acquired Tastes first.