Prosecutorial initiatives face many hurdles. Long-term solutions will require domestic capacity development, and a significant commitment of time and resources. In the interim, efforts should be made to staff and equip specialized teams of prosecutors and investigators who understand the specific challenges of pursuing accountability for system crimes. The five guiding considerations that should be applied to all prosecutorial initiatives include: (1) initiatives should be underpinned by a clear political commitment to accountability that understands the complex goals involved; (2) initiatives should have a clear strategy that addresses the challenges of a large universe of cases, many suspects, limited resources, and competing demands; (3) initiatives should be endowed with the necessary capacity and technical ability to investigate and prosecute the crimes in questions; (4) initiatives should pay particular attention to victims, ensuring their meaningful participation and ensuring adequate protection of witnesses; and (5) initiatives should be executed with a clear understanding of the relevant law and an appreciation of trial management skills, as well as a strong commitment to due process. This tool addresses the challenges of prosecuting perpetrators of crimes such as genocide, crimes against humanity, and war crimes. Prosecutions form one of the central elements of an integrated transitional justice strategy. It seeks to draw on lessons from past experiences with limitations. The tool presumes that long-term and sustainable solutions to impunity should aim mostly at building domestic capacity to try these crimes, and focuses mainly on the strategic and technical challenges that these prosecutions face domestically.