This book addresses the need for policing scholarship to strengthen its empirical cumulative knowledge base by replicating and reproducing earlier studies.The chapters in this volume advance policing research by replicating and reproducing earlier studies, investigating the generalizability of research findings, and making data and research methods available to other researchers to encourage scientific exploration of previous research findings. Each chapter addresses important scientific goals of validity, reliability, and generalizability, which build our cumulative knowledge of what is known in policing research, ultimately informing policymaking. The book offers insights into why replicating and reproducing policing scholarship is critical; from emphasizing the importance of making data and study material publicly available to facilitate replications and reproductions, to reproducing studies in new contexts and cautioning against making policy-making decisions based on studies that have not been replicated.This volume highlights the immense value in shifting researchers’ priorities – even slightly – to focus less so on originality and innovation to make room for replications and reproductions, thereby shedding light on how true, empirical knowledge on policing and police practice is dependent on it. This book was originally published as a special issue of Police Practice and Research.