Ronald Levandusky (plaintiff) lived as a tenant-shareholder at One Fifth Avenue Apartment Corporation (One Fifth Avenue) (defendant), a residential cooperative in New York City. Levandusky wanted to renovate his kitchen, but the cooperative board denied Levandusky a variance to relocate a steam riser in the process. The board’s decision was based in part on the opinion of an engineer who cautioned against making any changes to an old heating system. Levandusky relocated the steam riser without the board’s consent. One Fifth Avenue issued a stop-work order, and Levandusky petitioned the court to set aside the order. The trial court granted Levandusky’s petition, ruling that One Fifth Avenue’s decision to stop the work was arbitrary and capricious. On reargument, the trial court withdrew its decision, because the court had erroneously applied a standard of reasonableness when it should have applied the business judgment rule and deferred to the board’s decision. The appellate division reversed, ruling that the stop-work order was, in fact, subject to a standard of reasonableness and that One Fifth Avenue had unreasonably denied Levandusky the variance. One Fifth Avenue appealed.