The U.S. Army fought World War II with matériel much of which was developed in the decade prior to our entry, particularly in the period following the German blitz in Poland. Our efforts to develop munitions to the point where our armies could cope on equal terms with those of potential enemies are covered here in this, the first of three projected volumes on the history of the Ordnance Department in World War II. How well the Ordnance Department succeeded in matching the Germans in quality continues to be a matter of debate both within the Ordnance Department itself, and between the using arms and the Department. That the battle of quantity was won-with the help of a superb industrial machine-can hardly be denied. This volume, the result of diligent research by Dr. Constance McL. Green and her associates, should interest not only military men but also scientists, industrialists, and laymen in general. Among other things, it shows the urgent necessity of a directed, continuous, and intensive research program and the danger in failing to recognize and profit by developments abroad. Also shown is the inherent time interval between the drawing board and the production of the end item in quantity.