John Hagan is a prominent sociologist known for his work in the fields of criminology and social theory. He has contributed significantly to understanding the relationship between crime, social structures, and individual behavior. Hagan's research often focuses on issues such as juvenile delinquency, crime rates, and the impact of social inequality on criminal behavior. In addition to his research, Hagan has authored and co-authored several influential books and articles. He is also recognized for his role in academia, having served as a professor at Northwestern University. His work has helped shape contemporary discussions around criminal justice and the sociological aspects of crime.