It is first shown that the simple form of linear wear/load relation of the adhesive and abrasive wear laws arises from the nature of the asperity distribution. Without recourse to specific wear mechanisms, simple concepts for material properties, size of wear particles, and the production of wear particles are introduced. This procedure leads to an increasing appreciation of those factors which might be embraced by the specific wear constant. Of particular interest is the role of ductility in wear behavior. Finally, these ideas are extended to deal with the wear of surface films where it is seen that the film thickness is of paramount importance. Some experimental evidence for the concepts used is also provided.