This chapter concentrates primarily on the production of molds in which individual outsoles known as unit outsoles are formed. It addresses production of outsoles using those molds, how outsoles may be modified after they are molded, the process of cutting outsoles from sheet and calendered stock, and how other production variables that occur may be relevant in a forensic examination. Several methods are used in the production of outsole molds. Some methods have been in use for decades while newer ones are the product of constantly evolving technology and the competitive nature of the world footwear market. Prior to the 1990s, hand milling was the most common method of mold making in the world. In the mid to late 1980s, computer-aided design and computer-aided manufacture (CAD–CAM) were gradually developed for the design and production of outsole molds. The cast method involves the production of a casting master model created either by hand or with the CAD–CAM process.