Hanley & Another v. Donoghue is a landmark case in the United States Supreme Court that established the modern law of negligence. The case involved a dispute between two parties, Donoghue and the manufacturer of a ginger beer, Hanley & Another. Donoghue had purchased a bottle of ginger beer from a café and drank it, only to find a decomposed snail in the bottle. Donoghue sued Hanley & Another for negligence, claiming that the manufacturer had failed to take reasonable care in the production of the ginger beer. The Supreme Court held that the manufacturer had a duty of care to Donoghue, and that the manufacturer had breached that duty by failing to take reasonable care in the production of the ginger beer. The Court also established the concept of proximate cause, which states that a person can be held liable for damages caused by their negligence if the damages were foreseeable. This case established the modern law of negligence and is still cited in courts today.

In the case of Hanley & Another v. Donoghue, the Supreme Court was asked to decide whether a contract between two parties should be enforced even though it had been made without consideration. The majority opinion held that since there was no consideration given for the contract, it could not be enforced and thus must be declared void. However, Justice Field dissented from this decision on the grounds that while consideration is generally required in order for a contract to be enforceable, an exception can exist when one party has already performed their part of an agreement prior to any dispute arising over its validity or lack thereof. In such cases, he argued that equity demands that justice prevail and so contracts should still remain binding despite being made without consideration if one party has already fulfilled their obligations under said agreement.