Since people usually try to avoid being seen when committing a crime, improving surveillance opportunities appears to be a fruitful area for crime prevention efforts. However, the consequences of being seen by members of the public are often not serious for offenders, since many people do not notice crimes and others may not act appropriately if they do see a crime occurring. Measures to increase the capacity of people in residential neighborhoods to provide surveillance are also likely to have minimal impact, largely because of the relatively low incidence of crime in these areas and the disproportionate efforts required to effect surveillance. However, measures to extend the surveillance capabilities of employees, at least in the higher risk settings, appear to be more viable. Training employees to undertake a more directed surveillance role and designing the places where they work to aid this role are two ways of improving surveillance by employees. The use of surveillance aids such as closed circuit television may also be appropriate in particularly vulnerable areas. Further research should focus on determining offenders' perceptions of the risks involved in being seen and evaluating the existing options for surveillance. A bibliograpy listing 380 references is located at the end of the volume containing this paper.