Short answers, pulled from the story.
A contract is an agreement that specifies certain legally enforceable rights and obligations between two or more parties. It typically involves consent to transfer goods, services, money, or a promise to transfer any of those at a future date. Contract law is based on the principle that agreements must be honoured.
In common law jurisdictions, forming a contract generally requires an offer, an acceptance, consideration, and mutual intent to be bound. The acceptance must not vary the offer's terms, under the mirror image rule. A purported acceptance that changes the terms is a counteroffer and a rejection of the original offer.
Consideration is something of value given in exchange for the fulfilment of a promise, described by Lord Dunedin in Dunlop v Selfridge as the price for which the promise of the other is bought. Common law jurisdictions require consideration for a simple contract to be binding, while civil and most mixed-law jurisdictions require only a meeting of the minds. The UNIDROIT Principles of International Commercial Contracts reject the doctrine outright.
Carlill v Carbolic Smoke Ball Co was a nineteenth-century English case in which a pharmaceutical company advertised a smoke ball that would prevent flu if sniffed three times daily for two weeks, promising £100 to anyone who used it and still fell ill, and stating it had deposited £1,000 in the Alliance Bank. The Court of Appeal held that a reasonable man would see this as a serious offer and that the reward was a contractual promise.
Remedies for breach of contract generally include damages, such as compensatory, liquidated, nominal, or punitive damages, and forms of specific relief such as specific performance, injunctions, declaratory relief, and rescission. Common law jurisdictions prefer to award damages where possible, while civil law jurisdictions are more inclined toward specific relief. Specific performance is typically reserved for cases where damages are insufficient, such as the sale of real property.
Common law jurisdictions typically require contracts to include consideration to be valid, whereas civil and most mixed-law jurisdictions require only a meeting of the minds. Civil law itself contains distinct families, including the German tradition with its doctrine of abstraction, Napoleonic Code systems, and Roman-Dutch law. Jurisdictions that were British colonies generally adopted English common law, while others adopted German or French civil codes.
Misrepresentation is a false statement of fact made by one party to another before a contract that induces that party into the contract. A finding of misrepresentation allows for rescission and sometimes damages depending on the type, and it can occur by words or conduct according to Gordon v Selico. In Singapore and the United Kingdom, the Misrepresentation Act 1967 provides that even innocent misrepresentations can be grounds for damages.