This practitioner guide synthesizes findings from a three-city evaluation of gunshot detection technology (GDT) to guide law enforcement and government officials in decisions to invest in, continue, or expand the technology in efforts to reduce violent crime. The evaluation finds that GDT is most effective when law enforcement agencies thoroughly incorporate the technology into day-to-day procedures and operations and when the data generated by GDT is integrated into other data and investigative systems. The guidebook details best practices in GDT training, policy development, deployment, alert response, use in investigations, and communication with community members. Key recommendations include developing clear policies and procedures prior to GDT implementation, placing GDT sensors in areas where violent crime is most concentrated, making training an ongoing priority, and communicating with community members early and often.