Here are the testings of the Human Engineering Laboratory, launched at Stevens Institute, and now with branches in Boston, Chicago, near Philadelphia, Cleveland, as well as Hoboken. For some 20 years proof has been accumulated showing that scientific study of natural abilities has much to offer the individual as a preventative against the waste of time, energy, satisfaction, happiness. The six hour tests for the 13 aptitudes have shown that a combination of aptitudes, plus skill and knowledge acquired to augment them, point the way to full capacity, full use of basic talents. The testing can be given children as young as 9; to adults at any age, whether to help in change of job, or to discover ways of making for fuller living. There is here substantial proof that the measures of strong points and weak, the indications of capabilities to be developed, have been successful. The tests themselves are described, illustrations through cases, and applications of using these aptitudes in compatible work are detailed to show how the measuring has worked out. An interesting study from vocational and career angle, in the fuller explanation department for industries, personal lives and juvenile guidance.