193 N.Y. 349 (1908)
Clark v. West is a seminal case in the realm of contract law, particularly regarding the waiver of conditions.
Can a party to a contract waive a condition, and if so, under what circumstances is such a waiver considered valid?
A party to a contract may waive a condition by conduct inconsistent with an intention to enforce the condition, particularly when it indicates a voluntary relinquishment of a known right.
The New York Court of Appeals held that West Publishing Company, by accepting Clark's work despite his drinking, had waived the condition of abstinence, thus entitling Clark to the full payment outlined in the contract.
Clark v. West is a landmark decision on the doctrine of waiver of conditions in contracts. It illustrates how courts may interpret the actions of parties as implied waiver of contractual terms and conditions, impacting how contracts are negotiated and enforced. This case is a cornerstone for understanding the legal distinction between waiver (an intentional relinquishment of a right) and modification (a change to the terms of the contract), and helps demarcate the boundaries of permissible behavior under contractual obligations.