I'm in the middle of Bruce Schneier's Beyond Fear. It's a really magnificent piece of work, one of the few almost-perfect "bridge" books. He conveys complex ideas about security in complex systems in a readily understandable manner, without ever compromising that this is a tricky, often counter-intuitive field..
He has an excellent essay on why voting machines are hinky as hell, and the very simple way to fix them. How simple? Two. Steps. And he makes one of my favorite points, one that ties into some things going on in the media distribution world - secrecy is not security.