This book has developed from the material presented in a course on "Psychological Tests in Vocational Guidance and Selection" which the writer was invited to conduct in Teachers' College, Columbia University. The widespread interest in vocational psychology which has grown up in recent years, the eagerness with which even the most superficial and absurd systems of "character analysis" are being adopted and tried out, and especially the lack of references, offering conservative evaluation, to which inquirers may be directed, have made it seem advisable to publish the material in systematic form. The book is essentially a presentation of the problems and methods of that branch of applied psychology which deals with individual differences in mental constitution. In the present instance only those differences are considered which may seem to be significant in determining the individual's choice of a vocation, or in influencing the selection of workers from among a group of applicants or candidates. It is the writer's hope that the book may be suggestive to the individual who seeks to know himself better, helpful to the student and parent who may desire to avoid the wiles of the charlatan, encouraging to the investigator or counsellor who is engaged in carrying forward the solution of vocational problems, and useful to the practical man who may be mainly interested in surrounding himself with competent associates and employees. To all those whose published works are referred to in the bibliography, as well as to many not therein mentioned, the writer is under heavy obligations. He is especially indebted to Professor F. G. Bonser, of Teachers' College, for the original invitation to formulate the material, and to Professor Joseph Jastrow, editor of the "Conduct of Mind" series, for most patient and helpful editorial criticism and suggestion. H. L. HOLLINGWORTH. Columbia University. * * * * * Transcriber's note: For Text: A word surrounded by underscores like _this_ signifies the word is italics in the text. For Numbers and Equations: Parentheses have been added to clarify fractions. Superscripts are designated with a caret and brackets, e.g. 11.1^{3} is 11.1 to the third power. Greek letters in equations are translated to their English version. Minor typos have been corrected and footnotes moved to the end of the sections. * * * * * CONTENTS CHAPTER PAGE I.--MOTIVES AND ANTECEDENTS OF VOCATIONAL PSYCHOLOGY 1 II.--THE SEARCH FOR PHRENOLOGICAL AND PHYSIOGNOMIC PRINCIPLES 21 III.--THE DEVELOPMENT OF PSYCHOLOGICAL TESTS 57 IV.--THE PSYCHOGRAPHIC METHODS 80 V.--SPECIAL VOCATIONAL TESTS AND METHODS 109 VI.--SELF-ANALYSIS AND THE JUDGMENT OF ASSOCIATES 122