Mateus Rennó Santos is an Assistant Professor in the Department of Criminology at the University of South Florida. He received his BA and MA in Sociology from the Federal University of Minas Gerais, in Brazil, and his PhD in Criminology and Criminal Justice from the University of Maryland, College Park. He was previously a consultant for the United Nations Office on Drugs and Crime, in Austria, a researcher at the Center for Crime and Public Safety Studies, in Brazil, and a member of the Maryland Data Analysis Center, at the University of Maryland. His research focuses on crime and criminal justice trends, particularly on the drivers of changes in the rates of violence of populations, and on testing macro-level criminological theory. His recent research explores the drivers of a worldwide decline in violence.