I must ask the reader's indulgence for this article's concern with applications of the stress concept, which are distinct from, although related to clinical medicine. It has not been my object to deal with the way physicians have been aided by stress research in the practice of medicine--that information is already widely available. Rather, I have attempted to sketch briefly the history of the stress theory and to demonstrate how this information can help anyone, physician or layman, lead a more complete and satisfying life. The applications of the stress theory have been dealt with at length elsewhere. I believe that we can find within scientifically verified observations the basis of a code of behavior suited to our century. The great laws of nature that regulate the defenses of living beings against stress of any kind are essentially the same at all levels of life, from individual cells to entire complex human organisms and societies. It helps a great deal to understand the fundamental advantages and disadvantages of catatoxic and syntoxic attitudes by studying the biologic basis of self-preservation as reflected in syntoxic and catatoxic chemical mechanisms. When applied to everyday problems, this understanding should lead to choices most likely to provide us the pleasant eustress (from the Greek eu meaning good, as in euphoria) involved in achieving fulfillment and victory, thereby avoiding the self-destructive distress of frustration and failure. So the translation of the laws governing resistance of cells and organs to a code of behavior comes down to three basic precepts: 1. Find your own natural stress level. People differ with regard to the amount and kind of work they consider worth doing to meet the exigencies of daily life and to assure their future security and happiness. In this respect, all of us are influenced by hereditary predispositions and the expectations of our society. Only through planned self-analysis can we establish what we really want; too many people suffer all their lives because they are too conservative to risk a radical change by breaking with hiabits or traditions. 2. Altruistic egoism. The selfish (i.e., self-interested) hoarding of the goodwill, respect, esteem, support, and love of our neighbors is the most efficient way to give vent to our pent-up energy and to create a more enjoyable, beautiful, or useful environment.3. Earn thy neighbor's love. This motto--which is merely a rewording of the command to "love thy neighbor as thyself"--is compatible with man's natural structure, and although it is based on altruistic egoism, it could hardly be attacked as unethical. Who would blame the man who wants to assure his own homeostasis and happiness only by accumulating the treasure of other poeple's benevolence and love? Yet this makes him virtually unassailable, for nobody wants to attack and destroy those upon whom he depends.