Bruce Schneier became one of my favorite writers after I read his excellent Secrets and lies: digital security in a networked world. He was and is an expert security tech guy, but his focus has changed over time to the behavioral aspects of security. The chapter called The Human Factor explains why people are the weakest link in any security system. Good stuff.
He also posts often to his security blog. Timely and interesting. I liked the 4/30 article on the biometric fingerprint reader in the gym. I guess no one wrote a "sweaty guy with barbell indents on his fingertips" use case.