The violent crimes considered are murder, manslaughter, and assault. The dissertation is based on several studies made by the author during the years 1978-84. The Gavle Study covered all violent crimes reported to the police during the years 1968-70 and 1973-75 in a medium-sized Swedish municipality. The 21 Police Districts Study was a comparison of violent criminality in Swedish cities. The Big City Crime Study focused on violent crime in Stockholm. In three studies, statistical analyses were performed on data from police and other local records. In addition, information was used from a cohort study, a regional variations study, and a Stockholm violent crime study, all conducted by other groups. Part 1 focuses on the problems caused by unreported ('hidden') criminality, since the study results presented are based on reported crimes recorded by the police. Part 2 focuses on offender profiles and the circumstances of the offenses. In Part 3, the ecological aspects -- where and when -- of violent offenses are considered. This section includes chapters on the temporal patterns of violent criminality, urban-rural differences in the rate and structure of violent criminality, interurban and intraurban variations in crime rate and structure in relation to city and ward characteristics, and regional patterns of violence in relation to other social problems, such as alcohol consumption, alcohol abuse, and unemployment. A summary and discussion of some of the results presented compose the final part of the report. Recommendations for further research, 125 tables, 22 figures, 13 maps, 7 appendixes presenting more raw data, footnotes, and 249 references are supplied.