Terrorists typically plan their operations meticulously; and if allowed to complete their plans, they rarely fail. Plans are based on terrorist surveillance of targets, usually in the vicinity of the target's home or office. The detection of such surveillance should have high priority in any security program for potential terrorist targets. A basic surveillance-detection program has a number of steps. The first step is to determine what is normal in the vicinity of the home, office, and "choke" points (locations the target cannot avoid). These areas must then be constantly observed by persons trained in what to look for. Observations must be regularly communicated to supervisors. Once the surveillance information is obtained, it must be compared to the activities of the normal working environment. Computer programs are available for this analysis. If there is evidence of change in the normal environment, the system should identify this change. Information on specific changes must go to operatives in the field along with recommended actions.