To study the risks of abuse, violence, and homicide, 5 studies of groups at risk for violence are summarized. 192 Abused Infants, 181 Abused Children, 127 Homicidal Youth, 425 Assaulters, 223 Rapists, and 223 Molesters were randomly selected and tracked in court, probation, medical, and school records, then compared with carefully matched groups of Controls and (in older groups) Nonviolent Delinquents. In adolescence or adulthood, these groups were classified into Later Homicidal (N = 234), Later Violent or Nonviolent Delinquent, and Later Nondelin-quent subgroups for more detailed comparisons. Shao's bootstrapped logistic regressions were applied to identify risks for commission of homicide. Significant predictors for all homicidal cases in these samples were number of court contacts, poorer executive function, lower social maturity, alcohol abuse, and weapon possession. Predictors for the 373 Abused cases (Infants and Children) were court contacts, injury, burn, poisoning, fetal substance exposure, and parental alcohol abuse. Predictors for the 871 Violent Delinquent cases (Assaulters, Rapists, Molesters) were court contacts, poorer executive function, and lower social maturity. Accuracies of prediction from the regressions ranged from 81% for homicidal sex offenders to 87 to 99% for other homicidal groups.