Knowles v. The Gaslight and Coke Company was a United States Supreme Court case that dealt with the issue of whether a contract between two parties was valid. The plaintiff, Knowles, had entered into a contract with the defendant, The Gaslight and Coke Company, to purchase a certain amount of coal. The contract stated that the coal was to be delivered to Knowles at a certain price. However, when the coal was delivered, it was of a lower quality than what was specified in the contract. Knowles then sued The Gaslight and Coke Company for breach of contract. The Supreme Court held that the contract was valid and enforceable. The Court reasoned that the contract was clear and unambiguous, and that the parties had agreed to the terms of the contract. The Court also held that the defendant had breached the contract by delivering coal of a lower quality than what was specified in the contract. As a result, the Court ordered The Gaslight and Coke Company to pay damages to Knowles for the breach of contract.

Justice Field delivered the dissenting opinion in Knowles v. The Gaslight and Coke Company, arguing that the majority's decision was contrary to established precedent. He argued that a contract between two parties should be enforced according to its terms unless there is fraud or mistake involved, which he did not believe was present in this case. Furthermore, he noted that it would be unfair for one party to benefit from another's breach of contract when no such agreement had been made by either side prior to entering into the agreement. Finally, Justice Field asserted that if a court were allowed to modify contracts without any evidence of fraud or mistake then it could lead to an unpredictable legal system where contracts are constantly being changed at will with no clear guidance on how they should be interpreted and enforced.