I just got finished reading Beyond Fear: Thinking Sensibly About Security in an Uncertain World by Bruce Schneier. This was an excellent book and covers security and terrorism topics with a layman in mind and doesn't cover any topic that the average person couldn't understand and appreciate. The book uses lots of real world examples to describe security practices and their related trade offs. It also provides a five step decision making process to determine if a security mechanism is worth implementing. To me this is the security world's equivilent of The Design of Everyday Things by Donald Norman. Norman's book opened my eyes to thinking about usability in everyday objects. Schneier's book has had the same effect on me regarding security and its technological and civil-liberties related trade offs. I can't recommend this book any higher and I also encourage people to signup for the author's monthly newsletter: Crypto-Gram.