I've got multiple copies of both of Tappan's books. His books were full of "original thought" about survivalism. After reading his books, its easy to see how many other survival authors merely copied what he said, or said the same thing but substituted different weapons. I think his books are mandatory reading--if you want to be a true survivalist. He truly is the Godfather of the survival movement.
I've read Howard Ruff's best selling book too. He again had some of the spotlight prior to Y2K, but he is pretty much gone again. Thing is, much of what he said in "How To Prosper During The Coming Bad Years" is still true, but nobody cares. Back when the book was a best seller, many in the main stream believed him and followed his advice. Now, many in the mainstream disregard him as some nut. But thats OK, because those who forget history are doomed to repeat it . . .