A complete practitioner's treatment of Article 9 for lenders, borrowers, sellers, and litigators. Part I sets the scope, including the transactions Article 9 reaches regardless of form and the ones it excludes. Part II works collateral classification, which controls perfection method, priority rules, and enforcement, and explains why misclassification is the most consequential early error. Part III covers attachment and the drafting of a security agreement that actually attaches, including the supergeneric description trap. Part IV covers the five perfection methods and which collateral requires which. Part V covers the financing statement, the debtor name rules, the seriously misleading standard and its search logic safe harbor, and the maintenance obligations that keep perfection alive. Part VI covers choice of law and what happens when debtors move, merge, or change names. Part VII is the priority ladder in full, including purchase money rules, control priority, buyers, lien creditors, and fixtures. Part VIII covers accounts receivable financing and the anti-assignment overrides. Part IX covers default and enforcement including repossession, disposition, and the rebuttable presumption rule. Part X covers bankruptcy. Part XI covers agricultural liens, consignments, and the 2022 amendments on digital assets. Part XII is the loan documentation architecture and Part XIII is the verification list.