Local navy library has a shelf for free books. Grabbed one some time ago:

Peake,H. Reader's Guide to Intelligence Periodicals. 1992

Just a small book of introduction of periodicals. Original price 19.95 dollars.

I have no use of it and today wanted to put it back to the shelf.

But then I typed "intelligence periodicals" in google.

I was amazed to find that this book now is being sold online from 39 to 99 dollars.

What a surprise. Maybe I can sell it for 25 bucks.