The development and standardization of the third edition of the Wechsler Intelligence Scale for Children-Revised (WISC-R) are described. The existence of documented historical trends was a significant factor in the project to revise the WISC-R, which is the most widely used intelligence battery in North America. Development of the third edition (WISC-III) began in the mid-1980's. An extensive array of research studies was conducted to enhance the subtest composition and characteristics of the third Wechsler factor. Improvements to the subtest included: (1) expanding the object assembly subtest; (2) adding modernized artwork; (3) improving the coding subtest; (4) extending the normative range of subtests; (5) minimizing item bias; and (6) beginning development of supplementary materials and tests. The major features of its predecessor were kept in the WISC-III for historical continuity. In addition, greater downward age compatibility was created because of the recent revision of the preschool scales. One flowchart illustrates the Wechsler Model of Intelligence. A 30-item list of references is included. (SLD)