The publishers offer this book primarily as a popular treatise on the measurement of intelligence by scientific methods.

Every effort has been made to conform to the soundest scientific principles, both in the preparation of the Mentimeter tests, around which the volume is largely written, and in the introductory and explanatory chapters, in which the principles of applied psychology, as they bear upon mental tests, are stated in popular language.

The Mentimeters are based upon Doctor Trabue’s experience (1) as Assistant in Educational Psychology at Teachers College, Columbia University, (2) as psychological investigator of the intellectual status of inmates of charitable institutions and of pupils in the public schools, (3) as author of various intellectual and educational scales, widely used by psychologists and educators, (4) as Chief Psychological Examiner in two of the largest Army camps, directing the intellectual examination of more than a hundred thousand soldiers, (5) as Captain in the Adjutant General’s Department, U. S. Army, measuring the intellectual abilities of men in the Aviation Service, and (6) as Assistant Professor in Columbia University, giving instruction in the theory and practice of intellectual measurements and directing the application of such measurements to tens of thousands of school pupils.

Frank Parker Stockbridge, Doctor Trabue’s collaborator, is an author and journalist of a high order. As managing editor of Popular Mechanics and contributor to the World’s Work, Harper’s, Popular Science Monthly, etc., he has been thrown into contact with important affairs in the world of science so that he is especially equipped to work with Doctor Trabue in presenting this interesting subject. As director of the publicity campaign of the American Library Association War Fund his contact with the Army and the results of the biggest experiment in the way of psychological tests that the world has ever seen was invaluable to him in this work. The publishers feel that the collaboration is a particularly happy one.

The success of the scientific method of testing intelligence among both officers and men in the Army has directed widespread attention to the general subject. The Mentimeter is the first comprehensive system of tests, applicable to the whole range of educational and industrial requirements, to be offered for general use.

To employers and those in charge of the selection, grading, and promotion of workers of every class, in factories, offices, and stores; to teachers of all grades, from kindergarten to university; to parents who are interested in ascertaining, and watching the growth of their children’s mental development and to young men and young women striving for self-improvement and advancement and desirous of learning something of their own mental capacities and limitations as a guide to the intelligent choice of vocations or professions, the publishers offer this book in the confident belief that it will be found of real service.