Routledge is now re-issuing this prestigious series of 204 volumes originally published between 1910 and 1965. The titles include works by key figures such asC.G. Jung, Sigmund Freud, Jean Piaget, Otto Rank, James Hillman, Erich Fromm, Karen Horney and Susan Isaacs. Each volume is available on its own, as part of a themed mini-set, or as part of a specially-priced 204-volume set. A brochure listing each title in the "International Library of Psychology" series is available upon request.

This is Volume VIII of twenty-one in the Individual Differences series with the library of Psychology. First published in 1929, this study provides information on the principles of mental tests and examinations within the area of interrogation in order to understand more fully the differences in the minds of individuals.

Many of the earliest books, particularly those dating back to the 1900s and before, are now extremely scarce and increasingly expensive. We are republishing many of these classic works in affordable, high quality, modern editions, using the original text and artwork.