This guide covers customs compliance end to end, in the order an importer encounters it: classification, valuation, origin and marking, entry and liquidation, and the dispute mechanisms that follow. Classification chapters walk the General Rules of Interpretation in their required order and explain how contested classifications are actually worked. Valuation chapters cover the transaction value hierarchy, the statutory additions with particular attention to assists, and related party pricing. Origin chapters distinguish substantial transformation from tariff shift rules and explain why a good can have different origins for different purposes. Compliance chapters address the importer's duty of reasonable care, recordkeeping, broker oversight, audits, and the prior disclosure mechanism that converts an eight-figure penalty exposure into interest. Later chapters cover rulings, protests, judicial review with the presumption of correctness, trade remedies, drawback, and the special regimes that defer or recover duty.