This supplement to the first edition of Contract Law: Rules, Cases, and Problems features key black letter rules, plus comments and illustrations, from the Restatement (Second) of Contracts and state adoptions of the Uniform Commercial Code. The supplement features virtually all of the black letter rules of law that a typical student would wish to consult in working through the materials in a typical contracts class, including the 2022 UCC amendments that introduce the "hybrid transaction" and "controllable electronic records" (blockchain) concepts. This supplement is designed primarily for use in conjunction with Contract Law: Rules, Cases, and Problems insofar as it shares that casebook's organization. However, this supplement can be used to supplement any Contract Law casebook.