The history of intelligence testing merits study as standardized intelligence tests have been administered for only a little over a century. The most popular tests in use today are the Wechsler scales, despite the availability of other test batteries that are better grounded in contemporary theory. To understand why contemporary revisions of Wechsler's tests continue to dominate the field of cognitive assessment, it is necessary to understand how Wechsler radically changed the concept of psychological assessment. Evidence from Wechsler's own publications, as well as evidence from other primary sources were used in order to correct some of the mistakes in the literature. Each subtest that formed part of Wechsler's original battery, the Wechsler-Bellevue, was reviewed in this study. This review also reveals that contrary to assertions that Wechsler's original scale was developed without regard to theory, his test was in fact grounded in the most popular intelligence and personality theories of his day. A body of research exists that supports some of the traditional criticisms of contemporary cognitive assessment specifically for being unable to measure some aspects of human decision making. Measurement of these constructs might give psychologists the ability to predict occurrences of irrational and illogical behavior. Wechsler would most likely agree with these criticisms and urge test developers to continue to refine their tests in order to measure constructs that aid in understanding the examinee's personality. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]