Allen, Leana CristineThroughout U.S. history, the military has served as one of the largest employers and educators of young men and women. As such, it has had a great influence in the lives of a large proportion of the U.S. population. Despite the potential impact of military service in later life, little research attention has focused on this topic, particularly in criminology. The few studies that have examined the relationship between military service and criminal behavior tend to have ignored pre-military characteristics, and results vary depending on the time period during which the sample served in the military. This study applies a life course framework to the question of how military service influences later criminal behavior. The main purpose of this research is to determine whether military service changes existing trajectories of criminal behavior and/or whether the military provides another setting for the continuation of pre-military behavior patterns. Other important considerations include selection into the military, the timing of military service in an individual's life, and the historical context of service. For example, do those who enter the military at an earlier age experience greater change in criminal behavior than those who enter later in life? Additionally, does the influence of military service on criminal behavior differ by historical context? To address these questions, this study uses four data sets; three birth cohorts (1942, 1945, and 1949) and the National Longitudinal Survey of Youth. Men in these samples served during different historical periods from the beginning of the Vietnam War to the early period of the all-volunteer force. Statistical methods were used to account for potential differences in selection and the presence of unobserved heterogeneity. Results suggest that there is an important influence of military service on later criminal behavior, but the specific direction of the effect depends on the historical period in which service occurred. In particular, serving in the military during the Vietnam era was related to reduced offending, and service during the volunteer era was related to increased offending. These results were significant even after controlling for race, education, socioeconomic status, age, and prior criminal behavior patterns.en-USDissertation