In introducing the subject of valve steels to this Society I do so, not because of any special knowledge which I possess, but on account of the general interest which is being taken in the subject at the present time. It is quite evident that the valve steels which have been regularly used are not satisfactorily meeting all the present conditions, and therefore advances will have to be made, especially as much greater engine efficiencies are being demanded. Presumably the valve has to withstand much severer conditions than formerly. In many cases the result, as far as the valve is concerned, means a higher working temperature, which in turn affects many other properties of the steel such as scaling, the tendency to air-harden, etc.