Keyser v. Farr is a United States Supreme Court case that was decided in 1881. The case involved a dispute between two parties over a contract for the sale of a steamboat. The plaintiff, Keyser, had entered into a contract with the defendant, Farr, to purchase a steamboat for $2,000. Keyser paid the full amount, but Farr refused to deliver the boat. Keyser then sued Farr for breach of contract. The Supreme Court held that Farr was liable for breach of contract. The Court found that Farr had failed to fulfill his obligations under the contract and that Keyser was entitled to damages. The Court also held that Farr was liable for the full amount of the contract, plus interest, as well as any other damages that Keyser may have suffered as a result of the breach. The Court's decision in Keyser v. Farr established that a party who breaches a contract is liable for the full amount of the contract, plus any damages that the other party may have suffered as a result of the breach. This decision has been cited in numerous subsequent cases and is still used today to determine the liability of parties in breach of contract cases.

Justice Field delivered the dissenting opinion in Keyser v. Farr, arguing that the majority's decision was incorrect and should be reversed. He argued that under California law, a married woman had an absolute right to her separate property which could not be taken away from her by any act of hers or her husband's without a court order. The majority held that since Mrs. Keyser had signed over title to certain real estate to Mr. Farr with knowledge of its value and no consideration being given for it, she was estopped from claiming ownership of it later on when their marriage ended in divorce proceedings initiated by herself against him; however Justice Field disagreed with this conclusion because he believed there were other legal remedies available to protect Mr. Farr’s interests instead of using estoppel as grounds for denying Mrs. Keyser’s claim on the property rights she possessed prior to signing them over during their marriage - such as lien or mortgage laws - which would have been more appropriate than relying solely upon estoppel principles here where none existed before between these parties at issue in this case nor did they exist after either party took action regarding said real estate transaction between themselves while still married but now divorced due each having acted independently without consulting one another beforehand about what may happen if/when they ever split up afterwards