Funny you should write about this subject, I found my PDR in a pile of garbage just outside a Dr's office that was moving. I walked by this place twice a day and the PDR was about 2 years old when I saw and grabbed it. It pays to pay attention to the garbage that's been put out on the street.

I also try to make the Library Book Sales when they are getting rid of their old books and pubs. That's where I picked up my "National Guardsman Manual", among others.

Having some old books on the shelves has another side effect: friends see the old books that you have and then they give you their old books because they know that you will take care of them. That's how I came into possession of "Fortunes in Formulas" (3rd ed/1935???) with it's foreword by Thomas Alvin Edison. To a proper survivalist, with a pessimistic view of humanity, this book is PRICELESS!!!