Contracts
Formation
A contract requires offer, acceptance, consideration, and no defenses. An offer must be definite enough to enforce and must manifest present intent to be bound. Acceptance is effective on dispatch (mailbox rule) unless the offer provides otherwise; option contracts, firm offers under UCC 2-205, and unilateral contracts are exceptions. Consideration is a bargained-for exchange - past consideration and moral obligation generally fail, except where a statute bars the original claim (moral obligation revival) or where a debt is time-barred.
UCC Versus Common Law
The UCC governs goods; common law governs services, land, and intangibles. UCC 2-207 handles the battle of the forms: additional terms in an acceptance between merchants become part of the contract unless they materially alter it or the offer expressly limits acceptance to its terms. The UCC also relaxes the statute of frauds (written confirmation between merchants) and the perfect-tender rule.
Defenses and Remedies
Watch for the statute of frauds (land, one year, surety, marriage, goods over $500, executor promises), fraud, duress, unconscionability, and mistake. Expectation damages place the plaintiff where performance would have; consequential damages require foreseeability (Hadley v. Baxendale); liquidated damages must be a reasonable forecast of probable loss.
Traps
Questions test whether an acceptance was a counteroffer (mirror image rule at common law), whether the mailbox rule applies to options (it doesn't), and whether a modification needs consideration (UCC 2-209 does not).
Rule of thumb
Identify the governing law first; it determines nearly every downstream rule.