This monograph presents critical reviews of recent applications of diagnostic psychological methods in the fields of counseling, psychotherapy, psychosomatic medicine, psychiatry and child development. Recent advances in the construction of mental tests and the interpretation of these tests are described and discussed in detail. The probable direction of future development of such tests and their application in research fields is considered. Six lectures are included by authors who are stated to be authorities in their particular fields. The consensus of comment made about present testing methods appears to be that many of the present day technics are both cumbersome and awkward and only by simplification of them will it be possible to obtain satisfactory information that can be of greater use both clinically and experimentally. A chapter relating to the problems of diagnostic technics with children is particularly interesting.