This publication from the Laura and John Arnold Foundation (LJAF) examines how police officers, emergency workers, housing officials, judges, case workers, doctors, and nurses can contribute to solving the problem of “frequent utilizers”—those who cycle in and out of jails, hospitals, shelters, and other social service programs at a high rate. Frequent utilizers are unique in that they cycle through not just one but multiple systems, and they often have a combination of hard-to-treat issues such as addiction, mental illness, chronic health problems, and homelessness. LJAF and communities at the forefront are gathering data and testing new systems and treatment options; the report argues that more communities need to join the effort and work to identify who is cycling through their criminal justice and health care systems, and why. This will require unprecedented partnerships between public safety personnel, health professionals, and service providers, including the ability to securely link interagency data. LJAF’s Data-Driven Justice project is working with jurisdictions to improve their ability to collect such information.