This publication is a guide for implementing recommendations of the Criminal Justice/Mental Health Consensus Project. Based on information from the Consensus Project Report, and interviews with dozens of successful advocates, this handbook examines five crucial steps that should underlie any advocacy effort to reverse the overrepresentation of people with mental illness in the criminal justice system: Step 1) Understand the Issue discusses the extent of the problem, the implications of the problem, the sources of the problem, and the solutions to the problem. Step 2) Anticipate Frequently Asked Questions discusses how advocates who reach out to practitioners and policymakers in the criminal justice and mental health systems must educate officials and staff members, all of whom may become potential partners, by anticipating and answering their most frequently asked questions. Step 3) Understand and Know Your Audience discusses knowing and understanding the perspectives of law enforcement, courts, corrections, juvenile justice, mental health providers, and elected officials and explain why addressing the issue is in their best interest and be able to propose initiatives mutually beneficial to each. Step 4) Take Action discusses how to document the problem, engage the media, serve as trainer for the criminal justice staff, hold a local or State-wide forum, form a community-wide coalition, launch a campaign or organization, build advocacy alliances with criminal justice partners, and provide peer and family support services. Step 5) Leverage Resources examines some of the resources available to advocates such as the Criminal Justice/Mental Health Consensus Project, and the Gains Center for Evidence-Based Practices along with reports, technical assistance, information about promising programs, and funding sources.