It is a recognized natural phenomenon that every effect is the result of a certain cause, or of a combination of causes, and that each effect is itself, in turn, the cause of additional effects. Action and reaction are the basis of natural law. Cause and effect, the latter being the cause of further effects, follow each other in ceaseless succession in the world of human affairs. Except by putting proper natural causes into action, it is impossible to produce the effect desired. It follows that specific knowledge of causes is necessary for the planned production of specific effects. Toward the accumulation of such knowledge the methods of science (pages 1 and 2) are constantly directed. The uncertainties of war are largely the outgrowth of the fact that the minds of men are pitted against one other. Because of this, a knowledge of the manner in which the human mind seeks its way out of difficulties is a great military asset. Consideration is next given, therefore, to the natural mental processes employed (page 11) and to certain human tendencies which have been known to militate against their successful employment. The mental processes employed by the normal mature human being before taking deliberate action, or in making studied provision for possible future action, are natural procedures, in that they employ the intellectual powers bestowed by nature, without artificial modification or embellishment. When the individual concerned has a background of adequate knowledge and experience, his ability to solve problems is limited only by his native intellectual endowment. That he falls short does not necessarily indicate, however, that the limit of native endowment has been reached. It happens frequently that latent powers have not been cultivated, or have not been utilized. A problem is, by definition, a perplexing question. In any human activity, a problem appears when a perplexity arises as to a way out of a difficulty inherent in a situation. The question involved then is, what is a way, more especially the best way, out of the seeming difficulty? To determine the best way out of the difficulty, i.e., the best solution of the problem, involves: (1) The establishment of the proper basis for the solution of the problem, (2) The actual solution of the problem through the employment of the reasoning power in the consideration of various possible solutions and the selection of the best solution, and (3) The conclusion, i.e., the decision, embodying the best solution. Considered in greater detail, the process has its inception in a combination of circumstances, existent or assumed, which, constitutes a situation. No problem will result however, unless the situation involves an apparent difficulty. Even in such a case, a problem will result only if such involvement exists and gives rise to a perplexity as to a way, more especially as to the best way, out of the seeming difficulty.