A ferroelectric material exhibits two stable polarization states that can be switched from one to another by an electrical field. Therefore, ferroelectrics seem to be ideally suited for low-writing power nonvolatile memories. Consequently, the research using ferroelectrics dates back to the 1950s with the first commercial memories coming to market in the early 1990s. However, the severe challenges of perovskite or layered perovskite ferroelectric materials into a CMOS process and the problems when realizing three-dimensional structures hindered the scaling below 100nm. The discovery of ferroelectricity in hafnium oxide has not only changed the scaling prospects of the traditional capacitor-based ferroelectric random access memories but also finally enabled a scalable ferroelectric field-effect transistor. The latter is, due to its structure that is comparable to a modern standard MOS transistor, very easy to integrate into CMOS technology. This chapter gives an overview of the basics and the status of ferroelectric memories including novel concepts and an outlook on beyond memory applications.