This book reframes the study of multicide (that is, serial and mass murder) to use objective measures, and aims to expand our understanding of multicide offending through descriptive and inferential statistical analyses of different homicide patterns of the offenders. Criminal homicide and multiple murders are rare occurrences that typically account for a very small percentage of all violent crimes in most countries. Despite this low occurrence, homicide continues to be an area of intense study, with a focus on subjective measures and classifications. The research and analysis based on a database of over 1,300 cases contributes to the criminological study of violence and draws distinctions between the types of offenders (partnered and solo, serial and mass, male and female, etc.) from a range of different countries and across decades. Traditionally, studies of homicide focus on male offenders and theories of offending are then applied to females and co-offenders. The research presented in this book reveals that women and partnered offenders have very different homicide patterns from men. Looking at the history of multicide offending, this book uses descriptive and inferential statistical analyses to directly compare differences in offending and outcome patterns across multicide offender types. This exploration of the multidimensionality of homicide at an international level is useful for scholars and students interested in criminal justice, criminology, psychology, sociology, or law.