This guide states the law governing modification and enforcement of family court orders. Part 1 distinguishes enforcement from modification and sets out the diagnostic framework. Part 2 covers administrative enforcement of support, including income withholding, interception, and license suspension. Part 3 covers contempt, its two forms, the elements, and the due process safeguards required before incarceration. Part 4 covers modification of support and custody, the change-in-circumstances standard, imputed income, and the bar on retroactive modification. Part 5 covers interstate enforcement under UIFSA, the UCCJEA, and the federal full faith and credit statutes. Part 6 covers international abduction. Later parts address property and retirement orders, parenting time enforcement, bankruptcy, tax, military pay, and state variations.