Books: Beyond Fear - Bruce Schneier

"And done correctly, this intuition-based sort of profiling can be an excellent security countermeasure. [Diana] Dean needed to have the training and the experience to profile accurately and properly, without stepping over the line and profiling illegally. The trick here is to make sure perceptions of risk match the actual risks. If those responsible for security profile based on superstition and wrong-headed intuition, or by blindly following a computerized profiling system, profiling won't work at all. And even worse, it actually can reduce security by blinding people to the real threats. Institutionalized profiling can ossify a mind, and a person's mind is the most important security countermeasure we have." -- from Beyond Fear by security expert Bruce Schneier