Recent events in Boston and Texas emphasize the importance of knowing what to do when an emergency occurs. Even as first responders rushed into help at both scenes, much of the initial care to the injured was provided by friends, neighbors and bystanders who were trained in CPR and first aid. Whether the emergency is community-wide and involves numerous injuries, or involves a single individual being hurt at home, it is vital that someone close by knows what to do when such an emergency occurs.