Harrison discusses her team’s research on female serial killers (FSKs) who committed their crimes in the US, beginning with FSK background. Topics include demographics, physical appearance, education, socioeconomic status, developmental history, family events, and age of first murder. The occupations of FSKs are discussed. Alarmingly, FSKs are often nurses, nurse’s aides, or other caregivers. The author compares her findings with those from other notable studies, such as from criminologist Eric Hickey. The rarity of empirical research on FSKs is underscored. The author describes her sample of FSKs derived using the mass media method of forensic research, examining information from newspapers, television networks, courts, government records, and historical societies. Harrison underscores the importance of incorporating and citing information from valid source material. Long-term effects of childhood maltreatment and a traumagenic background are underscored. To illustrate chapter concepts, the author presents the cases of FSKs Dorothea Puente and Jane Toppan and revisits the case of FSK Aileen Wuornos.