SACSI stemmed from a commitment by the U.S. Department of Justice to replicate in a number of pilot sites the effective design and efforts of Operation Ceasefire in Boston, which helped reduce youth violence and homicide in the city. In the SACSI sites, the process involved the following elements: the development of a strategic partnership; the use of research and information to assess the specific nature and dynamics of the targeted problem; a strategy to have a substantial short-term impact on the targeted crime problem; implementation of the strategy; and evaluation of the strategy's impact and its modification as indicated. This process is similar to the PSN model to be implemented by U.S. Attorneys Offices. This article reviews the organizational structures that were apparently most effective under SACSI; problem-solving approaches that evolved; tactics that emerged; and their effectiveness in reducing violence. The explanation of the lessons learned in developing effective partnerships focuses on establishing the team, leadership, management, the power of including front-line practitioners in the partnerships, the significance of involving the community in the partnership, and the importance of an outside perspective in the partnership. Lessons regarding understanding the targeted crime problem focus on the violence problem in two of the SACSI sites and observations about the problem specification process. Lessons in developing a strategy focus on reducing poverty in high crime neighborhoods, eradicating drug demand, prosecution of all illegal gun carriers, parenting classes, and conflict-resolution training and anti-gang programming in the schools. Common tactics used in the sites and the measurement of outcomes are also discussed. Initial evaluation findings from the first five SACSI sites funded in 1998 are promising.