The smooth working and success of the Terrain Exercise depends almost entirely on the ability and tactical knowledge of the Director, the care he devotes to the selection of the ground, the preparation of the problem, and his own personal preparation for the conduct of the Terrain Exercise. To this end a study should be made of the tactical training it is desired to impart. A problem designed to bring out these points should be drawn up and fitted to the ground. The successive special situations must follow in logical sequence. The Director must have in his mind a solution of the various situations of the problem and must familiarize himself with all of its phases to the extent that he will be able to make reasonable answer to any question that may be propounded. He must receive all the ideas presented by the members of the class; take out the good and tactfully discard the poor and indifferent. He must take care that he does not unduly criticize the members of the class when they make mistakes and faulty dispositions. Above all, he must never hold up a solution to ridicule. Preparation of the Problem Having determined upon the tactical subject to be studied, the next essential is a problem, clearly and tersely stated, logically drawn and easily understood. The several tactical situations should follow one another in their natural sequence. Each should bring out the tactical points that it is desired to impress upon the members of the class. Long and complex situations, difficult for the average man to grasp, should be avoided. Situations should be interesting and instructive, natural and simple. The next step is to fit the problem to a particular section of the terrain that may be available. In this connection it is well to draw up a tentative problem with its several situations. Then go out on the ground and fit the problem to it. The Director should carefully work out on the ground beforehand the several situations that he desires to develop. He should work out the details of all possible solutions and prepare himself to discuss the advantages and disadvantages of measures that may be proposed by members of the class and to state the solution that he, himself, prefers, with the reasons therefor. A sufficient number of copies of the initial problem, together with the special situations, should be prepared so that a copy may be available for each member of the class. This is a more satisfactory method than the Director explaining them verbally. Time is saved and misunderstandings avoided. The special situations are numbered serially and issued at the proper time, as the Exercise progresses. It is a good idea to have an envelope in which to carry the cards or slips of paper bearing each special situation. General Conduct of a Terrain Exercise The problem will ordinarily consist of a general situation and several situations.