The vast majority of the research on cyberbullying has focused on children and adolescents in middle school or high school and has demonstrated strong links with both internalizing problems (such as anxiety, depression, or suicidal ideation) and externalizing problems (such as aggression, suspensions from school, and drug and alcohol use). Whereas less research has been conducted on cyberbullying among working adults or romantic partners, the existing findings seem to indicate that electronic mistreatment is also prevalent in these other contexts, and it is associated with a host of negative outcomes for individuals and organizations. To date, however, no efforts have been made to bring together this research across contexts, age groups, and cultures to gain a fuller perspective of the impact of cyberbullying and similar forms of electronic mistreatment. The current edited book aims to take the first step to fill this gap in the research by reviewing the many contexts (e.g., school, workplace, and romantic relationships) and lenses (cross-culture and developmental) through which cyberbullying research can be viewed. In the first chapter, we provide an overview of research on cyberbullying, including discussion of issues with defining cyberbullying. We also provide a narrative introduction to the remaining chapters in the rest of the book.