This guide explains the law governing every entity that claims a share of a personal injury recovery, organized by payer type because each payer operates under a different legal framework. It covers ERISA plan reimbursement and the equitable-lien line running from Great-West through Sereboff, McCutchen, and Montanile, and explains why the self-funded versus insured distinction determines whether state made-whole and anti-subrogation laws apply. It covers the Medicare Secondary Payer framework, conditional payment recovery, the dispute and appeal process, and future-medicals treatment. It covers Medicaid's anti-lien provision as construed in Ahlborn, Wos, and Gallardo, and the allocation practice that follows. It covers state hospital and provider liens, workers' compensation liens and credits, federal programs including the Federal Medical Care Recovery Act, FEHBA, TRICARE, and the VA, and the equitable doctrines that limit recovery. It closes with negotiation strategy, disbursement discipline, and the malpractice exposure that lien work creates. Each part identifies the governing authority, the documents that control, and the arguments that actually reduce a claim.