Conduct generally associated with stalking--following, spying, unwanted calling/writing, accosting, harassing and threatening--has existed since the beginning of human history. Until recently, however, this behavior had never been labeled as a distinct pattern of deviant social behavior, let alone a crime. Not until passage of the first anti-stalking statute in California in 1990 did such behavior become illegal. Since then, legislators, criminal justice professionals and victim services providers have started to examine the nature of and psychological motivations behind stalking behavior. Even victims of stalking have come to identify themselves as a distinct and unique constituency by forming support groups to help one another cope with the aftermath of the crimes committed against them. New information, issues and challenges related to stalking come to light on a daily basis. The chapter discusses the definition of stalking, characteristics of stalkers and their victims, categories used to classify stalking cases, methods and motives of stalkers, the impact of stalking on victims and response strategies for victims being stalked.