The reader who is not prepared and willing to examine facts and at least to take all the ascertainable facts into consideration before forming his conclusions is not likely to be interested. The scientific method of character analysis or mental measurement is based upon the comparison of the largest possible collection of ascertained facts. Guess work has no place in it. Psychology has small dealings with intuition and instinct nor is it in any way derived from magic or concerned with the occult. There are no unfathomable mysteries. There is no fact about the operation of the human mind which cannot be subjected to scientific investigation and measurement by any intelligent person. The scientific method requires that every conclusion must square with the results obtained by the experimental application of all related facts or be discredited as worthless. Theories have no place in science, except as something to be disproved if possible, and a single fact which does not square with any theory disproves the theory. The scientific method of mental measurement has passed the theoretical stage. It has squared with the facts wherever it has been intelligently applied. It has been demonstrated in a wide range of business and industrial applications, in education and in its use in determining the qualities and fitness of officers and men in the Army and Navy. What it offers is the shortest, simplest, and most accurate means available of determining human capacities and qualities. Professor Terman has admirably summarized the advantages of the scientific method of testing intelligence, as follows: “1. It gives us a universal standard of comparison. The result is absolutely uninfluenced by the general intellectual level of the group with which the subject to be rated happens to be associated. It is like measuring the height of a house instead of estimating it by comparison with the height of surrounding buildings. “2. It multiplies enormously the significance of mental performance. It does this by making fine distinctions which would be overlooked by the method of offhand judgment. It is like placing a smeared glass under a microscope and discovering that the smear is a complicated network of organic matter. “3. The test method is objective; that is, free from the influence of personal bias. It gives approximately the same verdict to-day, next week, or next year. It does not change its opinion. More important still, the verdict will be approximately the same whoever makes the test, whether a relative, a stranger, a friend, or an enemy, provided only that the rules of procedure be rigidly followed.