In the third place, the psychologist can help the military psychological warfare operator by helping him maintain his sense of mission and of proportion. The deadliest danger of propaganda consists of its being issued by the propagandist for his own edification. This sterile and ineffectual amusement can disguise the complete failure of the propaganda _as_ propaganda. There is a genuine pleasure in talking back, particularly to an enemy. The propagandist, especially in wartime, is apt to tell the enemy what he thinks of him, or to deride enemy weaknesses. But to have told the Nazis, for example, "You Germans are a pack of murderous baboons and your Hitler is a demented oaf. Your women are slobs, your children are halfwits, your literature is gibberish and your cooking is garbage," and so on, would have stiffened the German will to fight. The propagandist must tell the enemy those things which the enemy will heed; he must keep his private emotionalism out of the operation. The psychologist can teach the propaganda operator how to be objective, systematic, cold. For combat operations, it does not matter how much a division commander may dislike the enemy; for psychological warfare purposes, he must consider how to persuade them, even though he may privately thirst for their destruction. The indulgence of hatred is not a working part of the soldier's mission; to some it may be helpful; to others, not. The useful mission consists solely of making the enemy stop fighting, by combat or other means. But when the soldier turns to propaganda, he may need the advice of a psychologist in keeping his own feelings out of it. Finally, the psychologist can prescribe media--radio, leaflets, loudspeakers, whispering agents, returned enemy soldiers, and so forth. He can indicate when and when not to use any given medium. He can, in conjunction with operations and intelligence officers, plan the full use of all available psychological resources. He can coordinate the timing of propaganda with military, economic or political situations. The psychologist does not have to be present in person to give this advice. He does not have to be a man with an M.D. or Ph. D. and years of postgraduate training. He can be present in the manuals he writes, in the indoctrination courses for psychological warfare officers he sets up, in the current propaganda line he dictates by radio. It is useful to have him in the field, particularly at the higher command headquarters, but he is not indispensable. The psychologist in person can be dispensed with; the methods of scientific psychology cannot. (Further on, throughout this book, reference will be made to current psychological literature. The general history of psychology is described in readable terms in Gregory Zilboorg and George W. Henry, _A History of Medical Psychology_, New York, 1941, and in Lowell S. Selling, _Men Against Madness_, New York, 1940, cheap edition, 1942.)