Hanauer v. Doane was a case heard by the United States Supreme Court in 1871. The case involved a dispute between two parties over a contract for the sale of a steamboat. The plaintiff, Hanauer, had entered into a contract with the defendant, Doane, to purchase a steamboat for $2,000. Doane had agreed to deliver the boat to Hanauer within a certain time frame, but failed to do so. Hanauer then sued Doane for breach of contract. The Supreme Court held that Doane was liable for breach of contract. The Court found that Doane had failed to fulfill his contractual obligations and that Hanauer was entitled to damages for the breach. The Court also held that Hanauer was entitled to recover the full amount of the purchase price, plus interest, as damages for the breach. The Court's decision in Hanauer v. Doane established the principle that a party who breaches a contract is liable for damages, including the full amount of the purchase price, plus interest. This decision has been cited in numerous subsequent cases and is still used today to determine the amount of damages that a party is entitled to recover for breach of contract.

In Hanauer v. Doane, the Supreme Court was asked to decide whether a will that had been revoked by its maker could be revived after his death. The majority of justices held that it could not, but Justice Field dissented from this opinion and argued that the will should be allowed to stand as valid. He reasoned that since there was no evidence of fraud or undue influence in the making of the original will, revoking it would go against public policy and undermine people's confidence in wills generally. Furthermore, he noted that allowing such revocation would create uncertainty for those who rely on wills for their inheritance rights and thus cause them harm without any corresponding benefit to society at large. Therefore, Justice Field concluded that if a testator has made an otherwise valid will which they later revoke during their lifetime then it should still remain valid after their death unless there is clear proof of fraud or undue influence involved in its creation or revocation