The March of Folly: From Troy to Vietnam (hc) by Barbara Tuchman for 1 dollar.
You might recall that I had begun reading and blogging this back in Aug. 07. As usual, my eyes were larger than my brain, and having checked out more books than I could finish before their return date, I ended up having to return the library copy I had checked out well before I finished it. (I never got past the skimming phase, in actuality.) When I went to recheck the book out the library no longer had a copy. I suspect that particular copy was sold at a library book sale.
So I was lucky enough to have someone donate a different copy to the library (my copy is a used book but not a retired library book) which I was then able to aquire.