Publisher Summary As soon as any wear test has been completed, the results need to be validated by examining the worn specimens, to ensure that the wear mechanism in the test is the same as that occurring in service. The specimens from the test and the worn components from service both need to be examined and compared. Samples obtained from laboratory wear tests have a clearly defined history: the worn area on the sample is often very clearly defined and little special preparation is needed. It is always important to carry out a visual examination of worn samples and components before using any other technique. This examination gives information about the whole component that other, higher resolution techniques can easily miss, such as smooth, shiny, rough, color, as well as the interrelationship between different features on the surface. The use of different lighting directions (vertical, oblique, glancing angle) can also be explored. If a much more detailed laboratory examination is required optical microscopes with magnifications up to 1500 times are available. The images reveal information about the color and placement of different features on the surface.