The Differential Aptitude Test (DAT) is a multiple aptitude battery designed to measure junior and senior high school students' and adults' ability to learn or succeed in certain areas. The test is suitable for group administration and is primarily for use in educational and vocational counseling, although it may be used in employee selection. The DAT contains two levels, with two equivalent alternate forms for each level. Eight subtests measure abilities. A score is provided for each subtest as well as for scholastic aptitude. Test administration procedures are easy to follow, and test materials are durable and reusable. The norming process for the edition was impressive, with about 170,000 students in the standardization samples. Evidence for reliability and validity is reviewed. The fact that the DAT has remained one of the most frequently used batteries is a tribute to its quality, credibility, and utility. The new items and new norming data of the most recent edition have improved the test while preserving psychometric quality. It would be worth pursuing concurrent validity data on the DAT in a few broadly defined occupational areas. (SLD)