Indeed, it may be questioned whether a “mute, inglorious Milton” ever existed. The world is full of people who regard themselves as “unappreciated.” Everyone is familiar with the unfortunate type that is forever seeking sympathy, constantly on the lookout for friendly shoulders on which to sob out the sad tale of the world’s harshness. Under psychological tests the preponderant majority of this type of individual is clearly demonstrated to be mentally deficient or sub-normal in some important respect. The occasional individual of normal mental capacity who fails to demonstrate that capacity by the performance of specific acts is merely mentally lazy. In other words, it may be set forth as a sound conclusion, capable of scientific proof, that mental capacity in the healthy, normal individual always finds means of expressing itself in concrete and socially useful ways, whenever its possessor actually desires so to utilize his mental powers. In the devising and preparation of tests intended to measure the less obvious of the mental powers, a considerable degree of ingenuity and the greatest amount of scientific care and technical skill is required. To the person untrained in psychology tests designed to measure the possession of the more abstract powers frequently look childish, if not positively silly. Since it is essential, in the case of Army officers and men, to determine as nearly as it may be done by simple and easily applied tests their possession of a wide variety of mental qualities, some of the elements of the Army Alpha test appear to the concrete type of mind to be futile, if not absurd. But any comprehensive system of mental tests must include, as there have been included in the Mentimeter tests presented in this volume, a considerable proportion which do not on their face appear to be directed toward the disclosure of the ordinary and useful mental capacities. It is of vital importance, if the results of any given series are to give an adequate picture of the actual abilities and possibilities of the subject examined, that tests of this character be included among them. Each of the possible classes of mental tests may be set to any one of an infinite number of standards. General intelligence tests, for example, may be set to the standard of the average university graduate, so that the result when applied to any individual gives a fair estimate of the subject’s intelligence as compared with that of those who have demonstrated the possession of mental capacity sufficient to complete satisfactorily a university course. Or the standard may be that of the average lawyer, the average high school pupil, the average normal child of any age or school grade, the average skilled mechanic, the average labourer, or the average child below the age of speech. And, in practice, what is measured is, after all, general intelligence.