This insightful volume examines key research questions concerning police decision to arrest as well as police-led diversion. The authors critically evaluate the tentative answers that empirical evidence provides to those questions, and suggest areas for future inquiry. Nearly seven decades of empirical study have provided extensive knowledge regarding police use of arrest. However, this research highlights important gaps in our understanding of factors that shape police decision-making and what is required to alter current police practice. Reviewing this research base, this brief takes stock of what is known empirically about all aspects related to the use of arrests, providing important insights on the knowledge needed to make evidence-based policy decisions moving forward. With the potential to better impact policy and programs for alternatives to arrest, this brief will appeal to researchers and practitioners in evidence-based policing and police decision-making, as well as those interested in alternatives to arrest and related fields such as public policy.