The article estimates the frequency with which firearms are used for self-protection by analyzing three telephone surveys of the general public in Canada and a fourth survey of the general public in the United States. Canadians report using firearms to protect themselves from dangerous people or animals between 60,000 and 80,000 times per year. Between 19,000 and 37,500 of these incidents involve defense against human threats. The results of the American survey confirm earlier estimates about the frequency of firearms used for self-protection in the United States. The findings of this study suggest that the private ownership of firearms offers benefits to the community as well as costs. Policymakers in both the United States and Canada should be aware that, by rendering it difficult for noncriminals to obtain a firearm when one is needed for defense, firearm bans may cost more lives than they save. Tables, notes, references