The primer outlines strategies for developing, coordinating, monitoring, and evaluating jail and prison-based programs and builds on lessons learned from two National Institute on Drug Abuse-funded studies, "Preventing Overdose Mortality Among People Exiting Incarceration" and "Optimizing Overdose Education and Naloxone Distribution Delivery in the United States."  At the end of each section is a Resource List of planning resources.  The Appendix contains information about existing jail-based and prison-based OEND programs and examples of documents and forms that can be adapted to address program needs.