This article focuses on the three basic groups of flexible-die forming methods: rubber pad, fluid cell, and fluid forming. It provides information on the Guerin process, the Verson-Wheelon process, the trapped-rubber process, the Marform process, the Hydroform process, the SAAB process, and the Demarest process. The article provides a discussion on the procedures of these processes, as well as the presses and tools used. It describes the methods of hydraulic forming of thin metal parts, namely, hydraulic forming with diaphragm, hydraulic forming with gasket and pressure control, and hydrobuckling.