Stress and fatigue are important factors in the decision making process. As such they should be areas of great interest and concern to the Navy, particularly in their relationship to the decision making capabilities of unrestricted line officers. Recent writings and experimentation in stress and fatigue are analyzed to point up the importance of these phenomena as they affect the unrestricted line officer, to examine the methods which the Navy might utilize in measuring and prediction, and to show applications which might be attempted in the areas of alleviation and control. The destroyer commanding officer is the criterion against which the stress and fatigue are measured. The conclusions are that fatigue and the effects of stress are, indeed, quite serious in their ramifications, that the Navy should be more cognizant of them, that positive programs can be established to reduce these effects at nominal cost, and that such programs might have valuable pay-offs in ships and lives.