The sport of American football has come under fire since some professional players have reported head injuries that have led to severe disabilities or even death. Football is very popular in the United States, so the ramifications of such findings are troubling for coaches, players, and fans. Researchers are studying the physical effects of head injuries, how to treat them, and how to prevent them in the first place. If you or someone you care about participates in a sport in which head injuries are common, where would you look for reliable information about the symptoms of a head injury and what to do about it?