Professionals working in the fields of trauma, victim assistance, mental health, law enforcement fire response, emergency medical services, and other professions are exposed to traumatic events regularly, in some cases daily. Vicarious trauma (VT) refers to the exposure to the trauma experiences of others, which is experienced regularly in all of the aforementioned professions. Research can assist the development of strategies for avoiding vulnerability to adverse impacts of this kind of work. In reviewing such research, the current article is organized by the four steps of a public health approach: 1) defining the problem, including measuring the scope or prevalence; 2) identifying risk and protective factors for negative outcomes; 3) developing interventions and policies; and 4) monitoring and evaluating interventions and policies over time. A research agenda for the field is put forward following these same steps. (Publisher abstract modified)