Source: The Annals of the American Academy of Political and Social Science, vol. 578, p. 35Systematic reviews use rigorous methods for locating, appraising, and synthesizing evidence from prior evaluation studies. They have explicit objectives, explicit criteria for including or excluding studies, and a structured and detailed report. The Campbell Collaboration Crime and Justice Group aims to prepare and maintain systematic reviews of criminological interventions and to make them accessible electronically to scholars, practitioners, policy makers, and the general public. The major challenges include setting methodological criteria for including studies in reviews, securing continued funding, academics needing publications in scholarly journals, and coping with the volume of work needed to maintain high standards, including refereeing proposals and final reviews and dealing with correspondence and unsolicited proposals. The aim of making the best knowledge about the effectiveness of criminological interventions immediately available to everyone is ambitious and very important.