A general review of some of the theories proposed to account for the process of bronze disease is presented from both the historical and chemical points of view. The corrosion product of most serious concern, cuprous chloride, and its interrelationship with some of the other important corrosion products of copper alloys, such as the copper trihydroxychlorides, is reviewed. The critical relative humidity for the transformation of cuprous chloride is discussed and suggestions are made concerning both the storage conditions for bronzes and the variety of conditions under which cuprous chloride can occur in excavated bronze.