Wear particles represent a crucial source of additional information in performing fundamental wear studies. It has also found important application in monitoring the deterioration of critical components in industrial machinery due to wear, notably in militarily-related machinery functions such as engines and gear transmission units. In this paper, a summary account is given of the way in which specific test machines have recently been utilized to produce wear debris under controlled test conditions. In particular, the morphological features of wear debris are described in relation to wear characteristics obtained from using three test machines: four-ball, pin-on-disc, and gear test machine, respectively. The results of subsequent microscope analysis and classification of the debris morphology are described in relation to the corresponding wear modes experienced in the test. The implications for application of a new software-based, wear debris classifier are reviewed and discussed in relation to present-day methods employed in the maintenance of military engines and gear transmission systems.