I first read that book about 1969 (Paperback). I read it again (same Paperback) about 20 years later. My wife purchased for me the hard bound edition about five years ago.....and I promptly read it again.
Each time I was amazed that it dealt with what was currently going on with our country. This tells me that the same crap will probably be going on in D.C. a hundred years from now. LOL
I had a similar experience....first read the book in 1964 and re-read it twice since then. Other than the Bible, it has had more influence on my life than any other book.