In Redfield, Executrix v. Ystalyfera Iron Company, the Supreme Court of the United States was asked to decide whether a contract between two parties was valid and enforceable. The plaintiff, Redfield, was the executrix of the estate of a deceased individual who had entered into a contract with the defendant, Ystalyfera Iron Company. The contract stated that the defendant would pay the plaintiff a certain amount of money in exchange for the plaintiff's promise to deliver a certain quantity of iron ore. The Supreme Court held that the contract was valid and enforceable. The Court found that the contract was supported by consideration, meaning that both parties had given something of value in exchange for the other's promise. The Court also found that the contract was not void for lack of mutuality of obligation, meaning that both parties had an obligation to perform under the contract. Finally, the Court held that the contract was not void for lack of capacity, meaning that both parties had the legal capacity to enter into the contract. Based on these findings, the Supreme Court held that the contract was valid and enforceable, and that the plaintiff was entitled to the money promised by the defendant.

In Redfield, Executrix v. Ystalyfera Iron Company, the Supreme Court was asked to decide whether a contract between two parties should be enforced in its entirety or if it could be modified by one of the parties without consent from the other. The majority opinion held that contracts are binding and cannot be unilaterally changed by either party; however, Justice Field dissented on this point. He argued that while contracts must generally remain intact as written, there may exist certain circumstances where modification is appropriate when both parties agree to such changes after they have been made. Furthermore, he noted that courts should not interfere with contractual agreements unless absolutely necessary and only then for good cause shown by one of the contracting parties.