The paper is devoted chiefly to those aspects of cooker design by which cooking performance is affected. Mechanical design is reviewed, but in much less detail, and mainly with the object of recording present practice.The question of the indication of the “heating condition” of ovens is discussed, and the desirability is stressed of taking account of radiation as well as air temperature. Consideration is given to the problem of oven ventilation, particularly from the point of view of its effect on “steaming” at the vent. The Advantages offered by thermostatic oven control are outlined and an attempt is made to forecast the changes, especially in connection with methods of heating and lagging, to which it is likely to lead.The history of the development of boiling-plates is briefly reviewed, and the relative advantages and disadvantages of the various methods of construction commonly employed in this country are discussed.