In Lewis v. Cocks, the United States Supreme Court was asked to decide whether a contract between two parties was valid and enforceable. The contract in question was an agreement between Lewis and Cocks, in which Lewis agreed to pay Cocks a certain sum of money in exchange for Cocks' promise to pay Lewis a certain sum of money at a later date. The Court held that the contract was valid and enforceable, and that Lewis was entitled to recover the money he had agreed to pay Cocks. The Court noted that the contract was not void for lack of consideration, as Cocks had promised to pay Lewis a certain sum of money at a later date. The Court also noted that the contract was not void for lack of mutuality of obligation, as both parties had agreed to perform certain obligations. Finally, the Court held that the contract was not void for lack of capacity, as both parties had the legal capacity to enter into a contract. In conclusion, the Court held that the contract between Lewis and Cocks was valid and enforceable, and that Lewis was entitled to recover the money he had agreed to pay Cocks.

In Lewis v. Cocks, the Supreme Court was asked to decide whether a patent for an invention of a new and useful improvement in fire-arms should be granted to the petitioner. The majority opinion held that it should not because there was no evidence that the invention had been reduced to practice or used by others prior to its application for patent protection. Justice Field dissented from this decision, arguing that even though there may have been some uncertainty as to when exactly the petitioner's invention had first been put into use, it did appear from all of the testimony presented at trial that he had invented something novel and useful which could be patented under existing law. He further argued that since Congress has provided for patents on inventions regardless of their novelty or utility, then so long as they are properly described in an application and meet other statutory requirements then they ought not be denied simply because someone else might have previously made use of them without obtaining legal protection.