On BoingBoing, Cory Doctorow calls Beyond Fear: Thinking Sensibly About Security in an Uncertain World "one of the most important texts of the decade." I'm pretty sure he means the decade starting in 2000, (or, say, September 11, 2001), not the last ten years.
Schneier's a/the security expert, and Beyond Fear, Cory says, "utterly demystifies security" for a non-technical audience. My bet is, it guts every Ashcroftian rights-and-power grab in the name of security like a trout on a church griddle. [I know, Ashcroft is so not Catholic, so the fish thing's not applicable. Work with me here, people.]
I'm using Schneier's landmark text, Applied Cryptography, as a reference for my animated musical script, of all things. After all, the video store's bargain bins are overflowing with tapes of animated musicals that included crypto but couldn't bother to get it right. Aren't they?