Mr. Hart is in charge of Oxford University Press and every stage of the Dictionary’s printing process. Based on the historical figure of the same name, Mr. Hart’s style guide, Hart’s Rules, sets the standard for everyone who works on the Dictionary. He is Gareth’s boss and often argues linguistic minutiae with Mr. Bradley and Dr. Murray. A demanding man, Mr. Hart’s frequent bouts of depression worsen when many Press men enlist in World War I.